The GDB/MI Interface
Function and Purpose
GDB/MI is a line based machine oriented text interface to GDB and is activated by specifying using the @option{--interpreter} command line option (see section Choosing modes). It is specifically intended to support the development of systems which use the debugger as just one small component of a larger system.
This chapter is a specification of the GDB/MI interface. It is written in the form of a reference manual.
Note that GDB/MI is still under construction, so some of the features described below are incomplete and subject to change.
Notation and Terminology
This chapter uses the following notation:
-
|
separates two alternatives. -
[ something ]
indicates that something is optional: it may or may not be given. -
( group )*
means that group inside the parentheses may repeat zero or more times. -
( group )+
means that group inside the parentheses may repeat one or more times. -
"string"
means a literal string.
Acknowledgments
In alphabetic order: Andrew Cagney, Fernando Nasser, Stan Shebs and Elena Zannoni.
GDB/MI Command Syntax
GDB/MI Input Syntax
command ==>
-
cli-command | mi-command
cli-command ==>
-
[ token ] cli-command nl
, where cli-command is any existing GDB CLI command. mi-command ==>
-
[ token ] "-" operation ( " " option )*
[
" --"]
( " " parameter )* nl token ==>
- "any sequence of digits"
option ==>
-
"-" parameter [ " " parameter ]
parameter ==>
-
non-blank-sequence | c-string
operation ==>
- any of the operations described in this chapter
non-blank-sequence ==>
- anything, provided it doesn't contain special characters such as "-", nl, """ and of course " "
c-string ==>
-
""" seven-bit-iso-c-string-content """
nl ==>
-
CR | CR-LF
Notes:
- The CLI commands are still handled by the MI interpreter; their output is described below.
-
The
token
, when present, is passed back when the command finishes. - Some MI commands accept optional arguments as part of the parameter list. Each option is identified by a leading `-' (dash) and may be followed by an optional argument parameter. Options occur first in the parameter list and can be delimited from normal parameters using `--' (this is useful when some parameters begin with a dash).
Pragmatics:
- We want easy access to the existing CLI syntax (for debugging).
- We want it to be easy to spot a MI operation.
GDB/MI Output Syntax
The output from GDB/MI consists of zero or more out-of-band records followed, optionally, by a single result record. This result record is for the most recent command. The sequence of output records is terminated by `(gdb)'.
If an input command was prefixed with a token
then the
corresponding output for that command will also be prefixed by that same
token.
output ==>
-
( out-of-band-record )* [ result-record ] "(gdb)" nl
result-record ==>
-
[ token ] "^" result-class ( "," result )* nl
out-of-band-record ==>
-
async-record | stream-record
async-record ==>
-
exec-async-output | status-async-output | notify-async-output
exec-async-output ==>
-
[ token ] "*" async-output
status-async-output ==>
-
[ token ] "+" async-output
notify-async-output ==>
-
[ token ] "=" async-output
async-output ==>
-
async-class ( "," result )* nl
result-class ==>
-
"done" | "running" | "connected" | "error" | "exit"
async-class ==>
-
"stopped" | others
(where others will be added depending on the needs--this is still in development). result ==>
-
variable "=" value
variable ==>
-
string
value ==>
-
const | tuple | list
const ==>
-
c-string
tuple ==>
-
"{}" | "{" result ( "," result )* "}"
list ==>
-
"[]" | "[" value ( "," value )* "]" | "[" result ( "," result )* "]"
stream-record ==>
-
console-stream-output | target-stream-output | log-stream-output
console-stream-output ==>
-
"~" c-string
target-stream-output ==>
-
"@" c-string
log-stream-output ==>
-
"&" c-string
nl ==>
-
CR | CR-LF
token ==>
- any sequence of digits.
Notes:
- All output sequences end in a single line containing a period.
-
The
token
is from the corresponding request. If an execution command is interrupted by the `-exec-interrupt' command, the token associated with the `*stopped' message is the one of the original execution command, not the one of the interrupt command. - status-async-output contains on-going status information about the progress of a slow operation. It can be discarded. All status output is prefixed by `+'.
- exec-async-output contains asynchronous state change on the target (stopped, started, disappeared). All async output is prefixed by `*'.
- notify-async-output contains supplementary information that the client should handle (e.g., a new breakpoint information). All notify output is prefixed by `='.
- console-stream-output is output that should be displayed as is in the console. It is the textual response to a CLI command. All the console output is prefixed by `~'.
- target-stream-output is the output produced by the target program. All the target output is prefixed by `@'.
- log-stream-output is output text coming from GDB's internals, for instance messages that should be displayed as part of an error log. All the log output is prefixed by `&'.
- New GDB/MI commands should only output lists containing values.
See section GDB/MI Stream Records, for more details about the various output records.
Simple Examples of GDB/MI Interaction
This subsection presents several simple examples of interaction using the GDB/MI interface. In these examples, `->' means that the following line is passed to GDB/MI as input, while `<-' means the output received from GDB/MI.
Target Stop
Here's an example of stopping the inferior process:
-> -stop <- (gdb)
and later:
<- *stop,reason="stop",address="0x123",source="a.c:123" <- (gdb)
Simple CLI Command
Here's an example of a simple CLI command being passed through GDB/MI and on to the CLI.
-> print 1+2 <- &"print 1+2\n" <- ~"$1 = 3\n" <- ^done <- (gdb)
Command With Side Effects
-> -symbol-file xyz.exe <- *breakpoint,nr="3",address="0x123",source="a.c:123" <- (gdb)
A Bad Command
Here's what happens if you pass a non-existent command:
-> -rubbish <- ^error,msg="Undefined MI command: rubbish" <- (gdb)
GDB/MI Compatibility with CLI
To help users familiar with GDB's existing CLI interface, GDB/MI accepts existing CLI commands. As specified by the syntax, such commands can be directly entered into the GDB/MI interface and GDB will respond.
This mechanism is provided as an aid to developers of GDB/MI clients and not as a reliable interface into the CLI. Since the command is being interpreteted in an environment that assumes GDB/MI behaviour, the exact output of such commands is likely to end up being an un-supported hybrid of GDB/MI and CLI output.
GDB/MI Output Records
GDB/MI Result Records
In addition to a number of out-of-band notifications, the response to a GDB/MI command includes one of the following result indications:
"^done" [ "," results ]
-
The synchronous operation was successful,
results
are the return values. "^running"
- The asynchronous operation was successfully started. The target is running.
"^error" "," c-string
-
The operation failed. The
c-string
contains the corresponding error message.
GDB/MI Stream Records
GDB internally maintains a number of output streams: the console, the target, and the log. The output intended for each of these streams is funneled through the GDB/MI interface using stream records.
Each stream record begins with a unique prefix character which
identifies its stream (see section GDB/MI Output Syntax). In addition to the prefix, each stream record contains a
string-output
. This is either raw text (with an implicit new
line) or a quoted C string (which does not contain an implicit newline).
"~" string-output
- The console output stream contains text that should be displayed in the CLI console window. It contains the textual responses to CLI commands.
"@" string-output
- The target output stream contains any textual output from the running target.
"&" string-output
- The log stream contains debugging messages being produced by GDB's internals.
GDB/MI Out-of-band Records
Out-of-band records are used to notify the GDB/MI client of additional changes that have occurred. Those changes can either be a consequence of GDB/MI (e.g., a breakpoint modified) or a result of target activity (e.g., target stopped).
The following is a preliminary list of possible out-of-band records. In particular, the exec-async-output records.
*stopped,reason="reason"
reason can be one of the following:
breakpoint-hit
- A breakpoint was reached.
watchpoint-trigger
- A watchpoint was triggered.
read-watchpoint-trigger
- A read watchpoint was triggered.
access-watchpoint-trigger
- An access watchpoint was triggered.
function-finished
- An -exec-finish or similar CLI command was accomplished.
location-reached
- An -exec-until or similar CLI command was accomplished.
watchpoint-scope
- A watchpoint has gone out of scope.
end-stepping-range
- An -exec-next, -exec-next-instruction, -exec-step, -exec-step-instruction or similar CLI command was accomplished.
exited-signalled
- The inferior exited because of a signal.
exited
- The inferior exited.
exited-normally
- The inferior exited normally.
signal-received
- A signal was received by the inferior.
GDB/MI Command Description Format
The remaining sections describe blocks of commands. Each block of commands is laid out in a fashion similar to this section.
Note the the line breaks shown in the examples are here only for readability. They don't appear in the real output. Also note that the commands with a non-available example (N.A.) are not yet implemented.
Motivation
The motivation for this collection of commands.
Introduction
A brief introduction to this collection of commands as a whole.
Commands
For each command in the block, the following is described:
Synopsis
-command args...
Result
GDB Command
The corresponding GDB CLI command(s), if any.
Example
GDB/MI Breakpoint table commands
This section documents GDB/MI commands for manipulating breakpoints.
The -break-after
Command
Synopsis
-break-after number count
The breakpoint number number is not in effect until it has been hit count times. To see how this is reflected in the output of the `-break-list' command, see the description of the `-break-list' command below.
GDB Command
The corresponding GDB command is `ignore'.
Example
(gdb) -break-insert main ^done,bkpt={number="1",addr="0x000100d0",file="hello.c",line="5"} (gdb) -break-after 1 3 ~ ^done (gdb) -break-list ^done,BreakpointTable={nr_rows="1",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x000100d0",func="main",file="hello.c",line="5",times="0", ignore="3"}]} (gdb)
The -break-condition
Command
Synopsis
-break-condition number expr
Breakpoint number will stop the program only if the condition in expr is true. The condition becomes part of the `-break-list' output (see the description of the `-break-list' command below).
GDB Command
The corresponding GDB command is `condition'.
Example
(gdb) -break-condition 1 1 ^done (gdb) -break-list ^done,BreakpointTable={nr_rows="1",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x000100d0",func="main",file="hello.c",line="5",cond="1", times="0",ignore="3"}]} (gdb)
The -break-delete
Command
Synopsis
-break-delete ( breakpoint )+
Delete the breakpoint(s) whose number(s) are specified in the argument list. This is obviously reflected in the breakpoint list.
GDB command
The corresponding GDB command is `delete'.
Example
(gdb) -break-delete 1 ^done (gdb) -break-list ^done,BreakpointTable={nr_rows="0",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[]} (gdb)
The -break-disable
Command
Synopsis
-break-disable ( breakpoint )+
Disable the named breakpoint(s). The field `enabled' in the break list is now set to `n' for the named breakpoint(s).
GDB Command
The corresponding GDB command is `disable'.
Example
(gdb) -break-disable 2 ^done (gdb) -break-list ^done,BreakpointTable={nr_rows="1",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="2",type="breakpoint",disp="keep",enabled="n", addr="0x000100d0",func="main",file="hello.c",line="5",times="0"}]} (gdb)
The -break-enable
Command
Synopsis
-break-enable ( breakpoint )+
Enable (previously disabled) breakpoint(s).
GDB Command
The corresponding GDB command is `enable'.
Example
(gdb) -break-enable 2 ^done (gdb) -break-list ^done,BreakpointTable={nr_rows="1",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="2",type="breakpoint",disp="keep",enabled="y", addr="0x000100d0",func="main",file="hello.c",line="5",times="0"}]} (gdb)
The -break-info
Command
Synopsis
-break-info breakpoint
Get information about a single breakpoint.
GDB command
The corresponding GDB command is `info break breakpoint'.
Example
N.A.
The -break-insert
Command
Synopsis
-break-insert [ -t ] [ -h ] [ -r ] [ -c condition ] [ -i ignore-count ] [ -p thread ] [ line | addr ] [-l [ <NUM> <NUM>...] ]
If specified, line, can be one of:
- function
- filename:linenum
- filename:function
- *address
The possible optional parameters of this command are:
- `-t'
- Insert a tempoary breakpoint.
- `-h'
- Insert a hardware breakpoint.
- `-c condition'
- Make the breakpoint conditional on condition.
- `-i ignore-count'
- Initialize the ignore-count.
- `-r'
- Insert a regular breakpoint in all the functions whose names match the given regular expression. Other flags are not applicable to regular expresson.
- `-l [<NUM> <NUM>...]'
- This list of indices will be used to select from the list of matches if there are multiple breakpoint hits. Passing -1 will cause all matches to be selected.
Result
The result is in the form:
^done,bkptno="number",func="funcname", file="filename",line="lineno",shlib="shlib"
or, if there are multiple breakpoints, and the -l option is not selected:
^done,matches=[b=[index="index",number="number",func="funcname", file="filename",line="lineno"], b=[]...]
where number is the GDB number for this breakpoint, funcname is the name of the function where the breakpoint was inserted, filename is the name of the source file which contains this function, and lineno is the source line number within that file, and shlib is the shared library in which the breakpoint was set.
If there are multiple matches, the second form is sent including the index element, and no breakpoints are set. This will allow the UI to put up some kind of picker. Then it can re-issue the command with the -l option, using the index values provided by the first result. If you just want multiple matches to be always selected, then send a selection list of -1 always.
Note: this format is open to change.
GDB Command
The corresponding GDB commands are `break', `tbreak', `hbreak', `thbreak', and `rbreak'.
Example
(gdb) -break-insert main ^done,bkpt={number="1",addr="0x0001072c",file="recursive2.c",line="4"} (gdb) -break-insert -t foo ^done,bkpt={number="2",addr="0x00010774",file="recursive2.c",line="11"} (gdb) -break-list ^done,BreakpointTable={nr_rows="2",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x0001072c", func="main",file="recursive2.c",line="4",times="0"}, bkpt={number="2",type="breakpoint",disp="del",enabled="y", addr="0x00010774",func="foo",file="recursive2.c",line="11",times="0"}]} (gdb) -break-insert -r foo.* ~int foo(int, int); ^done,bkpt={number="3",addr="0x00010774",file="recursive2.c",line="11"} (gdb)
The -break-list
Command
Synopsis
-break-list
Displays the list of inserted breakpoints, showing the following fields:
- `Number'
- number of the breakpoint
- `Type'
- type of the breakpoint: `breakpoint' or `watchpoint'
- `Disposition'
- should the breakpoint be deleted or disabled when it is hit: `keep' or `nokeep'
- `Enabled'
- is the breakpoint enabled or no: `y' or `n'
- `Address'
- memory location at which the breakpoint is set
- `What'
- logical location of the breakpoint, expressed by function name, file name, line number
- `Times'
- number of times the breakpoint has been hit
If there are no breakpoints or watchpoints, the BreakpointTable
body
field is an empty list.
GDB Command
The corresponding GDB command is `info break'.
Example
(gdb) -break-list ^done,BreakpointTable={nr_rows="2",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x000100d0",func="main",file="hello.c",line="5",times="0"}, bkpt={number="2",type="breakpoint",disp="keep",enabled="y", addr="0x00010114",func="foo",file="hello.c",line="13",times="0"}]} (gdb)
Here's an example of the result when there are no breakpoints:
(gdb) -break-list ^done,BreakpointTable={nr_rows="0",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[]} (gdb)
The -break-watch
Command
Synopsis
-break-watch [ -a | -r ]
Create a watchpoint. With the `-a' option it will create an access watchpoint, i.e. a watchpoint that triggers either on a read from or on a write to the memory location. With the `-r' option, the watchpoint created is a read watchpoint, i.e. it will trigger only when the memory location is accessed for reading. Without either of the options, the watchpoint created is a regular watchpoint, i.e. it will trigger when the memory location is accessed for writing. See section Setting watchpoints.
Note that `-break-list' will report a single list of watchpoints and breakpoints inserted.
GDB Command
The corresponding GDB commands are `watch', `awatch', and `rwatch'.
Example
Setting a watchpoint on a variable in the main
function:
(gdb) -break-watch x ^done,wpt={number="2",exp="x"} (gdb) -exec-continue ^running ^done,reason="watchpoint-trigger",wpt={number="2",exp="x"}, value={old="-268439212",new="55"}, frame={func="main",args=[],file="recursive2.c", fullname="/home/foo/bar/devo/myproject/recursive2.c",line="5"} (gdb)
Setting a watchpoint on a variable local to a function. GDB will stop the program execution twice: first for the variable changing value, then for the watchpoint going out of scope.
(gdb) -break-watch C ^done,wpt={number="5",exp="C"} (gdb) -exec-continue ^running ^done,reason="watchpoint-trigger", wpt={number="5",exp="C"},value={old="-276895068",new="3"}, frame={func="callee4",args=[], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"} (gdb) -exec-continue ^running ^done,reason="watchpoint-scope",wpnum="5", frame={func="callee3",args=[{name="strarg", value="0x11940 \"A string argument.\""}], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"} (gdb)
Listing breakpoints and watchpoints, at different points in the program execution. Note that once the watchpoint goes out of scope, it is deleted.
(gdb) -break-watch C ^done,wpt={number="2",exp="C"} (gdb) -break-list ^done,BreakpointTable={nr_rows="2",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x00010734",func="callee4", file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"}, bkpt={number="2",type="watchpoint",disp="keep", enabled="y",addr="",what="C",times="0"}]} (gdb) -exec-continue ^running ^done,reason="watchpoint-trigger",wpt={number="2",exp="C"}, value={old="-276895068",new="3"}, frame={func="callee4",args=[], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"} (gdb) -break-list ^done,BreakpointTable={nr_rows="2",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x00010734",func="callee4", file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"}, bkpt={number="2",type="watchpoint",disp="keep", enabled="y",addr="",what="C",times="-5"}]} (gdb) -exec-continue ^running ^done,reason="watchpoint-scope",wpnum="2", frame={func="callee3",args=[{name="strarg", value="0x11940 \"A string argument.\""}], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"} (gdb) -break-list ^done,BreakpointTable={nr_rows="1",nr_cols="6", hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"}, {width="14",alignment="-1",col_name="type",colhdr="Type"}, {width="4",alignment="-1",col_name="disp",colhdr="Disp"}, {width="3",alignment="-1",col_name="enabled",colhdr="Enb"}, {width="10",alignment="-1",col_name="addr",colhdr="Address"}, {width="40",alignment="2",col_name="what",colhdr="What"}], body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y", addr="0x00010734",func="callee4", file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"}]} (gdb)
GDB/MI Data Manipulation
This section describes the GDB/MI commands that manipulate data: examine memory and registers, evaluate expressions, etc.
The -data-disassemble
Command
Synopsis
-data-disassemble [ -s start-addr -e end-addr ] | [ -f filename -l linenum [ -n lines ] ] -- mode
Where:
- `start-addr'
-
is the beginning address (or
$pc
) - `end-addr'
- is the end address
- `filename'
- is the name of the file to disassemble
- `linenum'
- is the line number to disassemble around
- `lines'
- is the the number of disassembly lines to be produced. If it is -1, the whole function will be disassembled, in case no end-addr is specified. If end-addr is specified as a non-zero value, and lines is lower than the number of disassembly lines between start-addr and end-addr, only lines lines are displayed; if lines is higher than the number of lines between start-addr and end-addr, only the lines up to end-addr are displayed.
- `mode'
- is either 0 (meaning only disassembly) or 1 (meaning mixed source and disassembly).
Result
The output for each instruction is composed of four fields:
- Address
- Func-name
- Offset
- Instruction
Note that whatever included in the instruction field, is not manipulated directely by GDB/MI, i.e. it is not possible to adjust its format.
GDB Command
There's no direct mapping from this command to the CLI.
Example
Disassemble from the current value of $pc
to $pc + 20
:
(gdb) -data-disassemble -s $pc -e "$pc + 20" -- 0 ^done, asm_insns=[ {address="0x000107c0",func-name="main",offset="4", inst="mov 2, %o0"}, {address="0x000107c4",func-name="main",offset="8", inst="sethi %hi(0x11800), %o2"}, {address="0x000107c8",func-name="main",offset="12", inst="or %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"}, {address="0x000107cc",func-name="main",offset="16", inst="sethi %hi(0x11800), %o2"}, {address="0x000107d0",func-name="main",offset="20", inst="or %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"}] (gdb)
Disassemble the whole main
function. Line 32 is part of
main
.
-data-disassemble -f basics.c -l 32 -- 0 ^done,asm_insns=[ {address="0x000107bc",func-name="main",offset="0", inst="save %sp, -112, %sp"}, {address="0x000107c0",func-name="main",offset="4", inst="mov 2, %o0"}, {address="0x000107c4",func-name="main",offset="8", inst="sethi %hi(0x11800), %o2"}, [...] {address="0x0001081c",func-name="main",offset="96",inst="ret "}, {address="0x00010820",func-name="main",offset="100",inst="restore "}] (gdb)
Disassemble 3 instructions from the start of main
:
(gdb) -data-disassemble -f basics.c -l 32 -n 3 -- 0 ^done,asm_insns=[ {address="0x000107bc",func-name="main",offset="0", inst="save %sp, -112, %sp"}, {address="0x000107c0",func-name="main",offset="4", inst="mov 2, %o0"}, {address="0x000107c4",func-name="main",offset="8", inst="sethi %hi(0x11800), %o2"}] (gdb)
Disassemble 3 instructions from the start of main
in mixed mode:
(gdb) -data-disassemble -f basics.c -l 32 -n 3 -- 1 ^done,asm_insns=[ src_and_asm_line={line="31", file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ testsuite/gdb.mi/basics.c",line_asm_insn=[ {address="0x000107bc",func-name="main",offset="0", inst="save %sp, -112, %sp"}]}, src_and_asm_line={line="32", file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ testsuite/gdb.mi/basics.c",line_asm_insn=[ {address="0x000107c0",func-name="main",offset="4", inst="mov 2, %o0"}, {address="0x000107c4",func-name="main",offset="8", inst="sethi %hi(0x11800), %o2"}]}] (gdb)
The -data-evaluate-expression
Command
Synopsis
-data-evaluate-expression expr
Evaluate expr as an expression. The expression could contain an inferior function call. The function call will execute synchronously. If the expression contains spaces, it must be enclosed in double quotes.
GDB Command
The corresponding GDB commands are `print', `output', and
`call'. In gdbtk
only, there's a corresponding
`gdb_eval' command.
Example
In the following example, the numbers that precede the commands are the tokens described in section GDB/MI Command Syntax. Notice how GDB/MI returns the same tokens in its output.
211-data-evaluate-expression A 211^done,value="1" (gdb) 311-data-evaluate-expression &A 311^done,value="0xefffeb7c" (gdb) 411-data-evaluate-expression A+3 411^done,value="4" (gdb) 511-data-evaluate-expression "A + 3" 511^done,value="4" (gdb)
The -data-list-changed-registers
Command
Synopsis
-data-list-changed-registers
Display a list of the registers that have changed.
GDB Command
GDB doesn't have a direct analog for this command; gdbtk
has the corresponding command `gdb_changed_register_list'.
Example
On a PPC MBX board:
(gdb) -exec-continue ^running (gdb) *stopped,reason="breakpoint-hit",bkptno="1",frame={func="main", args=[],file="try.c",fullname="/home/foo/bar/devo/myproject/try.c",line="5"} (gdb) -data-list-changed-registers ^done,changed-registers=["0","1","2","4","5","6","7","8","9", "10","11","13","14","15","16","17","18","19","20","21","22","23", "24","25","26","27","28","30","31","64","65","66","67","69"] (gdb)
The -data-list-register-names
Command
Synopsis
-data-list-register-names [ ( regno )+ ]
Show a list of register names for the current target. If no arguments are given, it shows a list of the names of all the registers. If integer numbers are given as arguments, it will print a list of the names of the registers corresponding to the arguments. To ensure consistency between a register name and its number, the output list may include empty register names.
GDB Command
GDB does not have a command which corresponds to
`-data-list-register-names'. In gdbtk
there is a
corresponding command `gdb_regnames'.
Example
For the PPC MBX board:
(gdb) -data-list-register-names ^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7", "r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18", "r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29", "r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9", "f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20", "f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31", "", "pc","ps","cr","lr","ctr","xer"] (gdb) -data-list-register-names 1 2 3 ^done,register-names=["r1","r2","r3"] (gdb)
The -data-list-register-values
Command
Synopsis
-data-list-register-values fmt [ ( regno )*]
Display the registers' contents. fmt is the format according to which the registers' contents are to be returned, followed by an optional list of numbers specifying the registers to display. A missing list of numbers indicates that the contents of all the registers must be returned.
Allowed formats for fmt are:
x
- Hexadecimal
o
- Octal
t
- Binary
d
- Decimal
r
- Raw
N
- Natural
GDB Command
The corresponding GDB commands are `info reg', `info
all-reg', and (in gdbtk
) `gdb_fetch_registers'.
Example
For a PPC MBX board (note: line breaks are for readability only, they don't appear in the actual output):
(gdb) -data-list-register-values r 64 65 ^done,register-values=[{number="64",value="0xfe00a300"}, {number="65",value="0x00029002"}] (gdb) -data-list-register-values x ^done,register-values=[{number="0",value="0xfe0043c8"}, {number="1",value="0x3fff88"},{number="2",value="0xfffffffe"}, {number="3",value="0x0"},{number="4",value="0xa"}, {number="5",value="0x3fff68"},{number="6",value="0x3fff58"}, {number="7",value="0xfe011e98"},{number="8",value="0x2"}, {number="9",value="0xfa202820"},{number="10",value="0xfa202808"}, {number="11",value="0x1"},{number="12",value="0x0"}, {number="13",value="0x4544"},{number="14",value="0xffdfffff"}, {number="15",value="0xffffffff"},{number="16",value="0xfffffeff"}, {number="17",value="0xefffffed"},{number="18",value="0xfffffffe"}, {number="19",value="0xffffffff"},{number="20",value="0xffffffff"}, {number="21",value="0xffffffff"},{number="22",value="0xfffffff7"}, {number="23",value="0xffffffff"},{number="24",value="0xffffffff"}, {number="25",value="0xffffffff"},{number="26",value="0xfffffffb"}, {number="27",value="0xffffffff"},{number="28",value="0xf7bfffff"}, {number="29",value="0x0"},{number="30",value="0xfe010000"}, {number="31",value="0x0"},{number="32",value="0x0"}, {number="33",value="0x0"},{number="34",value="0x0"}, {number="35",value="0x0"},{number="36",value="0x0"}, {number="37",value="0x0"},{number="38",value="0x0"}, {number="39",value="0x0"},{number="40",value="0x0"}, {number="41",value="0x0"},{number="42",value="0x0"}, {number="43",value="0x0"},{number="44",value="0x0"}, {number="45",value="0x0"},{number="46",value="0x0"}, {number="47",value="0x0"},{number="48",value="0x0"}, {number="49",value="0x0"},{number="50",value="0x0"}, {number="51",value="0x0"},{number="52",value="0x0"}, {number="53",value="0x0"},{number="54",value="0x0"}, {number="55",value="0x0"},{number="56",value="0x0"}, {number="57",value="0x0"},{number="58",value="0x0"}, {number="59",value="0x0"},{number="60",value="0x0"}, {number="61",value="0x0"},{number="62",value="0x0"}, {number="63",value="0x0"},{number="64",value="0xfe00a300"}, {number="65",value="0x29002"},{number="66",value="0x202f04b5"}, {number="67",value="0xfe0043b0"},{number="68",value="0xfe00b3e4"}, {number="69",value="0x20002b03"}] (gdb)
The -data-read-memory
Command
Synopsis
-data-read-memory [ -o byte-offset ] address word-format word-size nr-rows nr-cols [ aschar ]
where:
- `address'
- An expression specifying the address of the first memory word to be read. Complex expressions containing embedded white space should be quoted using the C convention.
- `word-format'
-
The format to be used to print the memory words. The notation is the
same as for GDB's
print
command (see section Output formats). - `word-size'
- The size of each memory word in bytes.
- `nr-rows'
- The number of rows in the output table.
- `nr-cols'
- The number of columns in the output table.
- `aschar'
- If present, indicates that each row should include an ASCII dump. The value of aschar is used as a padding character when a byte is not a member of the printable ASCII character set (printable ASCII characters are those whose code is between 32 and 126, inclusively).
- `byte-offset'
- An offset to add to the address before fetching memory.
This command displays memory contents as a table of nr-rows by
nr-cols words, each word being word-size bytes. In total,
nr-rows * nr-cols * word-size
bytes are read
(returned as `total-bytes'). Should less than the requested number
of bytes be returned by the target, the missing words are identified
using `N/A'. The number of bytes read from the target is returned
in `nr-bytes' and the starting address used to read memory in
`addr'.
The address of the next/previous row or page is available in `next-row' and `prev-row', `next-page' and `prev-page'.
GDB Command
The corresponding GDB command is `x'. gdbtk
has
`gdb_get_mem' memory read command.
Example
Read six bytes of memory starting at bytes+6
but then offset by
-6
bytes. Format as three rows of two columns. One byte per
word. Display each word in hex.
(gdb) 9-data-read-memory -o -6 -- bytes+6 x 1 3 2 9^done,addr="0x00001390",nr-bytes="6",total-bytes="6", next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396", prev-page="0x0000138a",memory=[ {addr="0x00001390",data=["0x00","0x01"]}, {addr="0x00001392",data=["0x02","0x03"]}, {addr="0x00001394",data=["0x04","0x05"]}] (gdb)
Read two bytes of memory starting at address shorts + 64
and
display as a single word formatted in decimal.
(gdb) 5-data-read-memory shorts+64 d 2 1 1 5^done,addr="0x00001510",nr-bytes="2",total-bytes="2", next-row="0x00001512",prev-row="0x0000150e", next-page="0x00001512",prev-page="0x0000150e",memory=[ {addr="0x00001510",data=["128"]}] (gdb)
Read thirty two bytes of memory starting at bytes+16
and format
as eight rows of four columns. Include a string encoding with `x'
used as the non-printable character.
(gdb) 4-data-read-memory bytes+16 x 1 8 4 x 4^done,addr="0x000013a0",nr-bytes="32",total-bytes="32", next-row="0x000013c0",prev-row="0x0000139c", next-page="0x000013c0",prev-page="0x00001380",memory=[ {addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"}, {addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"}, {addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"}, {addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"}, {addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"}, {addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"}, {addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"}, {addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"}] (gdb)
The -display-delete
Command
Synopsis
-display-delete number
Delete the display number.
GDB Command
The corresponding GDB command is `delete display'.
Example
N.A.
The -display-disable
Command
Synopsis
-display-disable number
Disable display number.
GDB Command
The corresponding GDB command is `disable display'.
Example
N.A.
The -display-enable
Command
Synopsis
-display-enable number
Enable display number.
GDB Command
The corresponding GDB command is `enable display'.
Example
N.A.
The -display-insert
Command
Synopsis
-display-insert expression
Display expression every time the program stops.
GDB Command
The corresponding GDB command is `display'.
Example
N.A.
The -display-list
Command
Synopsis
-display-list
List the displays. Do not show the current values.
GDB Command
The corresponding GDB command is `info display'.
Example
N.A.
The -environment-cd
Command
Synopsis
-environment-cd pathdir
Set GDB's working directory.
GDB Command
The corresponding GDB command is `cd'.
Example
(gdb) -environment-cd /kwikemart/marge/ezannoni/flathead-dev/devo/gdb ^done (gdb)
The -environment-directory
Command
Synopsis
-environment-directory [ -r ] [ pathdir ]+
Add directories pathdir to beginning of search path for source files. If the `-r' option is used, the search path is reset to the default search path. If directories pathdir are supplied in addition to the `-r' option, the search path is first reset and then addition occurs as normal. Multiple directories may be specified, separated by blanks. Specifying multiple directories in a single command results in the directories added to the beginning of the search path in the same order they were presented in the command. If blanks are needed as part of a directory name, double-quotes should be used around the name. In the command output, the path will show up separated by the system directory-separator character. The directory-seperator character must not be used in any directory name. If no directories are specified, the current search path is displayed.
GDB Command
The corresponding GDB command is `dir'.
Example
(gdb) -environment-directory /kwikemart/marge/ezannoni/flathead-dev/devo/gdb ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" (gdb) -environment-directory "" ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" (gdb) -environment-directory -r /home/jjohnstn/src/gdb /usr/src ^done,source-path="/home/jjohnstn/src/gdb:/usr/src:$cdir:$cwd" (gdb) -environment-directory -r ^done,source-path="$cdir:$cwd" (gdb)
The -environment-path
Command
Synopsis
-environment-path [ -r ] [ pathdir ]+
Add directories pathdir to beginning of search path for object files. If the `-r' option is used, the search path is reset to the original search path that existed at gdb start-up. If directories pathdir are supplied in addition to the `-r' option, the search path is first reset and then addition occurs as normal. Multiple directories may be specified, separated by blanks. Specifying multiple directories in a single command results in the directories added to the beginning of the search path in the same order they were presented in the command. If blanks are needed as part of a directory name, double-quotes should be used around the name. In the command output, the path will show up separated by the system directory-separator character. The directory-seperator character must not be used in any directory name. If no directories are specified, the current path is displayed.
GDB Command
The corresponding GDB command is `path'.
Example
(gdb) -environment-path ^done,path="/usr/bin" (gdb) -environment-path /kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb /bin ^done,path="/kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb:/bin:/usr/bin" (gdb) -environment-path -r /usr/local/bin ^done,path="/usr/local/bin:/usr/bin" (gdb)
The -environment-pwd
Command
Synopsis
-environment-pwd
Show the current working directory.
GDB command
The corresponding GDB command is `pwd'.
Example
(gdb) -environment-pwd ^done,cwd="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb" (gdb)
GDB/MI Program control
Program termination
As a result of execution, the inferior program can run to completion, if it doesn't encounter any breakpoints. In this case the output will include an exit code, if the program has exited exceptionally.
Examples
Program exited normally:
(gdb) -exec-run ^running (gdb) x = 55 *stopped,reason="exited-normally" (gdb)
Program exited exceptionally:
(gdb) -exec-run ^running (gdb) x = 55 *stopped,reason="exited",exit-code="01" (gdb)
Another way the program can terminate is if it receives a signal such as
SIGINT
. In this case, GDB/MI displays this:
(gdb) *stopped,reason="exited-signalled",signal-name="SIGINT", signal-meaning="Interrupt"
The -exec-abort
Command
Synopsis
-exec-abort
Kill the inferior running program.
GDB Command
The corresponding GDB command is `kill'.
Example
N.A.
The -exec-arguments
Command
Synopsis
-exec-arguments args
Set the inferior program arguments, to be used in the next `-exec-run'.
GDB Command
The corresponding GDB command is `set args'.
Example
Don't have one around.
The -exec-continue
Command
Synopsis
-exec-continue
Asynchronous command. Resumes the execution of the inferior program until a breakpoint is encountered, or until the inferior exits.
GDB Command
The corresponding GDB corresponding is `continue'.
Example
-exec-continue ^running (gdb) @Hello world *stopped,reason="breakpoint-hit",bkptno="2",frame={func="foo",args=[], file="hello.c",fullname="/home/foo/bar/devo/myproject/hello.c",line="13"} (gdb)
The -exec-finish
Command
Synopsis
-exec-finish
Asynchronous command. Resumes the execution of the inferior program until the current function is exited. Displays the results returned by the function.
GDB Command
The corresponding GDB command is `finish'.
Example
Function returning void
.
-exec-finish ^running (gdb) @hello from foo *stopped,reason="function-finished",frame={func="main",args=[], file="hello.c",fullname="/home/foo/bar/devo/myproject/hello.c",line="7"} (gdb)
Function returning other than void
. The name of the internal
GDB variable storing the result is printed, together with the
value itself.
-exec-finish ^running (gdb) *stopped,reason="function-finished",frame={addr="0x000107b0",func="foo", args=[{name="a",value="1"],{name="b",value="9"}}, file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, gdb-result-var="$1",return-value="0" (gdb)
The -exec-interrupt
Command
Synopsis
-exec-interrupt
Asynchronous command. Interrupts the background execution of the target. Note how the token associated with the stop message is the one for the execution command that has been interrupted. The token for the interrupt itself only appears in the `^done' output. If the user is trying to interrupt a non-running program, an error message will be printed.
GDB Command
The corresponding GDB command is `interrupt'.
Example
(gdb) 111-exec-continue 111^running (gdb) 222-exec-interrupt 222^done (gdb) 111*stopped,signal-name="SIGINT",signal-meaning="Interrupt", frame={addr="0x00010140",func="foo",args=[],file="try.c", fullname="/home/foo/bar/devo/myproject/try.c",line="13"} (gdb) (gdb) -exec-interrupt ^error,msg="mi_cmd_exec_interrupt: Inferior not executing." (gdb)
The -exec-next
Command
Synopsis
-exec-next
Asynchronous command. Resumes execution of the inferior program, stopping when the beginning of the next source line is reached.
GDB Command
The corresponding GDB command is `next'.
Example
-exec-next ^running (gdb) *stopped,reason="end-stepping-range",line="8",file="hello.c" (gdb)
The -exec-next-instruction
Command
Synopsis
-exec-next-instruction
Asynchronous command. Executes one machine instruction. If the instruction is a function call continues until the function returns. If the program stops at an instruction in the middle of a source line, the address will be printed as well.
GDB Command
The corresponding GDB command is `nexti'.
Example
(gdb) -exec-next-instruction ^running (gdb) *stopped,reason="end-stepping-range", addr="0x000100d4",line="5",file="hello.c" (gdb)
The -exec-return
Command
Synopsis
-exec-return
Makes current function return immediately. Doesn't execute the inferior. Displays the new current frame.
GDB Command
The corresponding GDB command is `return'.
Example
(gdb) 200-break-insert callee4 200^done,bkpt={number="1",addr="0x00010734", file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"} (gdb) 000-exec-run 000^running (gdb) 000*stopped,reason="breakpoint-hit",bkptno="1", frame={func="callee4",args=[], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"} (gdb) 205-break-delete 205^done (gdb) 111-exec-return 111^done,frame={level="0",func="callee3", args=[{name="strarg", value="0x11940 \"A string argument.\""}], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"} (gdb)
The -exec-run
Command
Synopsis
-exec-run
Asynchronous command. Starts execution of the inferior from the beginning. The inferior executes until either a breakpoint is encountered or the program exits.
GDB Command
The corresponding GDB command is `run'.
Example
(gdb) -break-insert main ^done,bkpt={number="1",addr="0x0001072c",file="recursive2.c",line="4"} (gdb) -exec-run ^running (gdb) *stopped,reason="breakpoint-hit",bkptno="1", frame={func="main",args=[],file="recursive2.c", fullname="/home/foo/bar/devo/myproject/recursive2.c",line="4"} (gdb)
The -exec-show-arguments
Command
Synopsis
-exec-show-arguments
Print the arguments of the program.
GDB Command
The corresponding GDB command is `show args'.
Example
N.A.
The -exec-step
Command
Synopsis
-exec-step
Asynchronous command. Resumes execution of the inferior program, stopping when the beginning of the next source line is reached, if the next source line is not a function call. If it is, stop at the first instruction of the called function.
GDB Command
The corresponding GDB command is `step'.
Example
Stepping into a function:
-exec-step ^running (gdb) *stopped,reason="end-stepping-range", frame={func="foo",args=[{name="a",value="10"}, {name="b",value="0"}],file="recursive2.c", fullname="/home/foo/bar/devo/myproject/recursive2.c",line="11"} (gdb)
Regular stepping:
-exec-step ^running (gdb) *stopped,reason="end-stepping-range",line="14",file="recursive2.c" (gdb)
The -exec-step-instruction
Command
Synopsis
-exec-step-instruction
Asynchronous command. Resumes the inferior which executes one machine instruction. The output, once GDB has stopped, will vary depending on whether we have stopped in the middle of a source line or not. In the former case, the address at which the program stopped will be printed as well.
GDB Command
The corresponding GDB command is `stepi'.
Example
(gdb) -exec-step-instruction ^running (gdb) *stopped,reason="end-stepping-range", frame={func="foo",args=[],file="try.c", fullname="/home/foo/bar/devo/myproject/try.c",line="10"} (gdb) -exec-step-instruction ^running (gdb) *stopped,reason="end-stepping-range", frame={addr="0x000100f4",func="foo",args=[],file="try.c", fullname="/home/foo/bar/devo/myproject/try.c",line="10"} (gdb)
The -exec-until
Command
Synopsis
-exec-until [ location ]
Asynchronous command. Executes the inferior until the location specified in the argument is reached. If there is no argument, the inferior executes until a source line greater than the current one is reached. The reason for stopping in this case will be `location-reached'.
GDB Command
The corresponding GDB command is `until'.
Example
(gdb) -exec-until recursive2.c:6 ^running (gdb) x = 55 *stopped,reason="location-reached",frame={func="main",args=[], file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="6"} (gdb)
The -file-core-file
Command
Synopsis
-file-core-file corefile
Specify the core file to be debugger.
The -file-exec-and-symbols
Command
Synopsis
-file-exec-and-symbols file
Specify the executable file to be debugged. This file is the one from which the symbol table is also read. If no file is specified, the command clears the executable and symbol information. If breakpoints are set when using this command with no arguments, GDB will produce error messages. Otherwise, no output is produced, except a completion notification.
GDB Command
The corresponding GDB command is `file'.
Example
(gdb) -file-exec-and-symbols /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx ^done (gdb)
The -file-exec-file
Command
Synopsis
-file-exec-file file
Specify the executable file to be debugged. Unlike `-file-exec-and-symbols', the symbol table is not read from this file. If used without argument, GDB clears the information about the executable file. No output is produced, except a completion notification.
GDB Command
The corresponding GDB command is `exec-file'.
Example
(gdb) -file-exec-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx ^done (gdb)
The -file-list-exec-sections
Command
Synopsis
-file-list-exec-sections
List the sections of the current executable file.
GDB Command
The GDB command `info file' shows, among the rest, the same
information as this command. gdbtk
has a corresponding command
`gdb_load_info'.
Example
N.A.
The -file-list-exec-source-file
Command
Synopsis
-file-list-exec-source-file
List the line number, the current source file, and the absolute path to the current source file for the current executable.
GDB Command
There's no GDB command which directly corresponds to this one.
Example
(gdb) 123-file-list-exec-source-file 123^done,line="1",file="foo.c",fullname="/home/bar/foo.c" (gdb)
The -file-list-exec-source-files
Command
Synopsis
-file-list-exec-source-files
List the source files for the current executable.
GDB Command
There's no GDB command which directly corresponds to this one.
gdbtk
has an analogous command `gdb_listfiles'.
Example
N.A.
The -file-list-globals
Command
Synopsis
-file-list-globals -file file -shlib image print-values -filter filter_regex -constants constants
List the globals defined in file file and image image. If file is the empty string, then all globals in image are listed, and if both file and image are the empty string, then all globals are listed.
print-values has the same meaning as for `-stack-list-locals'.
filter_regex is optional. If provided, then all statics whose names match the regex will be filtered out.
constants is also optional. If provided, and set to 1, then no const statics will be printed with the exception of const pointers.
GDB Command
There's no GDB command which directly corresponds to this one.
Example
(gdb) -file-list-exec-source-files ^done,files=[ {file=foo.c,fullname=/home/foo.c}, {file=/home/bar.c,fullname=/home/bar.c}, {file=gdb_could_not_find_fullpath.c}] (gdb)
If there is more than one file, then the output will be a list of files with the file and the globals as the elements of the list, as in:
(gdb) -file-list-globals -file "" -shlib gdb --no-values ^done,file=[filename="../../gdb/src/mmalloc/keys.c",globals=[]],file=[filename="../../gdb/src/mmalloc/mmap-sup.c",globals=[]],...] (gdb)
And if there are more than one shared library, the output will contain a list of images, which will contain a list of files as above, for instance:
(gdb) -file-list-globals --file "" --shlib "" --no-values ^done,image=[imagename="/usr/lib/dyld"],image=[imagename="/usr/lib/libncurses.5.dylib"],image=[imagename="/usr/lib,image=[imagename="/build/gdb/gdb",file=[filename="../../gdb/src/mmalloc/keys.c",globals=[]],...]] (gdb)
The -file-list-shared-libraries
Command
Synopsis
-file-list-shared-libraries
List the shared libraries in the program.
GDB Command
The corresponding GDB command is `info shared'.
Example
N.A.
The -file-list-statics
Command
Synopsis
-file-list-statics -file file -shlib image print-values -filter filter_regex -constants constants
List the globals defined in file file and image image. If image is the empty string, then the first occurance of the file file is used.
file also accepts the special cookie *CURRENT FRAME*
in which
case the currently selected frame is used. You still have to provide an some
value for image, but it is ignored.
print-values has the same meaning as for `-stack-list-locals'.
filter_regex is optional. If provided, then all statics whose names match the regex will be filtered out.
constants is also optional. If provided and set to 1, then no const statics will be printed with the exception of const pointers.
GDB Command
There's no GDB command which directly corresponds to this one.
Example
(gdb) -file-list-statics -file breakpoint.c -shlib gdb --no-values ^done,statics=[{name="overlay_events_enabled"},{name="exception_catchpoint_throw_enabled"},...] (gdb)
The -file-list-symbol-files
Command
Synopsis
-file-list-symbol-files
List symbol files.
GDB Command
The corresponding GDB command is `info file' (part of it).
Example
N.A.
The -file-symbol-file
Command
Synopsis
-file-symbol-file file
Read symbol table info from the specified file argument. When used without arguments, clears GDB's symbol table info. No output is produced, except for a completion notification.
GDB Command
The corresponding GDB command is `symbol-file'.
Example
(gdb) -file-symbol-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx ^done (gdb)
Miscellaneous GDB commands in GDB/MI
The -gdb-exit
Command
Synopsis
-gdb-exit
Exit GDB immediately.
GDB Command
Approximately corresponds to `quit'.
Example
(gdb) -gdb-exit
The -gdb-set
Command
Synopsis
-gdb-set
Set an internal GDB variable.
GDB Command
The corresponding GDB command is `set'.
Example
(gdb) -gdb-set $foo=3 ^done (gdb)
The -gdb-show
Command
Synopsis
-gdb-show
Show the current value of a GDB variable.
GDB command
The corresponding GDB command is `show'.
Example
(gdb) -gdb-show annotate ^done,value="0" (gdb)
The -gdb-version
Command
Synopsis
-gdb-version
Show version information for GDB. Used mostly in testing.
GDB Command
There's no equivalent GDB command. GDB by default shows this information when you start an interactive session.
Example
(gdb) -gdb-version ~GNU gdb 5.2.1 ~Copyright 2000 Free Software Foundation, Inc. ~GDB is free software, covered by the GNU General Public License, and ~you are welcome to change it and/or distribute copies of it under ~ certain conditions. ~Type "show copying" to see the conditions. ~There is absolutely no warranty for GDB. Type "show warranty" for ~ details. ~This GDB was configured as "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi". ^done (gdb)
The -interpreter-exec
Command
Synopsis
-interpreter-exec interpreter command
Execute the specified command in the given interpreter.
GDB Command
The corresponding GDB command is `interpreter-exec'.
Example
(gdb) -interpreter-exec console "break main" &"During symbol reading, couldn't parse type; debugger out of date?.\n" &"During symbol reading, bad structure-type format.\n" ~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n" ^done (gdb)
The -inferior-tty-set
Command
Synopsis
-inferior-tty-set /dev/pts/1
Set terminal for future runs of the program being debugged.
GDB Command
The corresponding GDB command is `set inferior-tty /dev/pts/1'.
Example
(gdb) -inferior-tty-set /dev/pts/1 ^done (gdb)
The -inferior-tty-show
Command
Synopsis
-inferior-tty-show
Show terminal for future runs of program being debugged.
GDB Command
The corresponding GDB command is `show inferior-tty'.
Example
(gdb) -inferior-tty-set /dev/pts/1 ^done (gdb) -inferior-tty-show ^done,inferior_tty_terminal="/dev/pts/1" (gdb)
GDB/MI Stack Manipulation Commands
The -stack-info-frame
Command
Synopsis
-stack-info-frame
Get info on the selected frame.
GDB Command
The corresponding GDB command is `info frame' or `frame' (without arguments).
Example
(gdb) -stack-info-frame ^done,frame={level="1",addr="0x0001076c",func="callee3", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"} (gdb)
The -stack-info-depth
Command
Synopsis
-stack-info-depth [ max-depth ]
Return the depth of the stack. If the integer argument max-depth is specified, do not count beyond max-depth frames.
GDB Command
There's no equivalent GDB command.
Example
For a stack with frame levels 0 through 11:
(gdb) -stack-info-depth ^done,depth="12" (gdb) -stack-info-depth 4 ^done,depth="4" (gdb) -stack-info-depth 12 ^done,depth="12" (gdb) -stack-info-depth 11 ^done,depth="11" (gdb) -stack-info-depth 13 ^done,depth="12" (gdb)
The -stack-list-arguments
Command
Synopsis
-stack-list-arguments show-values [ low-frame high-frame ]
Display a list of the arguments for the frames between low-frame and high-frame (inclusive). If low-frame and high-frame are not provided, list the arguments for the whole call stack.
The show-values argument must have a value of 0 or 1. A value of 0 means that only the names of the arguments are listed, a value of 1 means that both names and values of the arguments are printed.
GDB Command
GDB does not have an equivalent command. gdbtk
has a
`gdb_get_args' command which partially overlaps with the
functionality of `-stack-list-arguments'.
Example
(gdb) -stack-list-frames ^done, stack=[ frame={level="0",addr="0x00010734",func="callee4", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"}, frame={level="1",addr="0x0001076c",func="callee3", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"}, frame={level="2",addr="0x0001078c",func="callee2", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="22"}, frame={level="3",addr="0x000107b4",func="callee1", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="27"}, frame={level="4",addr="0x000107e0",func="main", file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="32"}] (gdb) -stack-list-arguments 0 ^done, stack-args=[ frame={level="0",args=[]}, frame={level="1",args=[name="strarg"]}, frame={level="2",args=[name="intarg",name="strarg"]}, frame={level="3",args=[name="intarg",name="strarg",name="fltarg"]}, frame={level="4",args=[]}] (gdb) -stack-list-arguments 1 ^done, stack-args=[ frame={level="0",args=[]}, frame={level="1", args=[{name="strarg",value="0x11940 \"A string argument.\""}]}, frame={level="2",args=[ {name="intarg",value="2"}, {name="strarg",value="0x11940 \"A string argument.\""}]}, {frame={level="3",args=[ {name="intarg",value="2"}, {name="strarg",value="0x11940 \"A string argument.\""}, {name="fltarg",value="3.5"}]}, frame={level="4",args=[]}] (gdb) -stack-list-arguments 0 2 2 ^done,stack-args=[frame={level="2",args=[name="intarg",name="strarg"]}] (gdb) -stack-list-arguments 1 2 2 ^done,stack-args=[frame={level="2", args=[{name="intarg",value="2"}, {name="strarg",value="0x11940 \"A string argument.\""}]}] (gdb)
The -stack-list-frames
Command
Synopsis
-stack-list-frames [ low-frame high-frame ]
List the frames currently on the stack. For each frame it displays the following info:
- `level'
- The frame number, 0 being the topmost frame, i.e. the innermost function.
- `addr'
-
The
$pc
value for that frame. - `func'
- Function name.
- `file'
- File name of the source file where the function lives.
- `line'
-
Line number corresponding to the
$pc
.
If invoked without arguments, this command prints a backtrace for the whole stack. If given two integer arguments, it shows the frames whose levels are between the two arguments (inclusive). If the two arguments are equal, it shows the single frame at the corresponding level.
GDB Command
The corresponding GDB commands are `backtrace' and `where'.
Example
Full stack backtrace:
(gdb) -stack-list-frames ^done,stack= [frame={level="0",addr="0x0001076c",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="11"}, frame={level="1",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="2",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="3",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="4",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="5",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="6",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="7",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="8",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="9",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="10",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="11",addr="0x00010738",func="main", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="4"}] (gdb)
Show frames between low_frame and high_frame:
(gdb) -stack-list-frames 3 5 ^done,stack= [frame={level="3",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="4",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}, frame={level="5",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}] (gdb)
Show a single frame:
(gdb) -stack-list-frames 3 3 ^done,stack= [frame={level="3",addr="0x000107a4",func="foo", file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}] (gdb)
The -stack-list-locals
Command
Synopsis
-stack-list-locals print-values
Display the local variable names for the selected frame. If
print-values is 0 or --no-values
, print only the names of
the variables; if it is 1 or --all-values
, print also their
values; and if it is 2 or --simple-values
, print the name,
type and value for simple data types and the name and type for arrays,
structures and unions. In this last case, a frontend can immediately
display the value of simple data types and create variable objects for
other data types when the the user wishes to explore their values in
more detail. With an argument of 2, 3, or --create-varobjs
,
the command makes variable objects for all the variables.
GDB Command
`info locals' in GDB, `gdb_get_locals' in gdbtk
.
Example
(gdb) -stack-list-locals 0 ^done,locals=[name="A",name="B",name="C"] (gdb) -stack-list-locals --all-values ^done,locals=[{name="A",value="1"},{name="B",value="2"}, {name="C",value="{1, 2, 3}"}] -stack-list-locals --simple-values ^done,locals=[{name="A",type="int",value="1"}, {name="B",type="int",value="2"},{name="C",type="int [3]"}] (gdb)
The -stack-select-frame
Command
Synopsis
-stack-select-frame framenum
Change the selected frame. Select a different frame framenum on the stack.
GDB Command
The corresponding GDB commands are `frame', `up', `down', `select-frame', `up-silent', and `down-silent'.
Example
(gdb) -stack-select-frame 2 ^done (gdb)
GDB/MI Symbol Query Commands
The -symbol-info-address
Command
Synopsis
-symbol-info-address symbol
Describe where symbol is stored.
GDB Command
The corresponding GDB command is `info address'.
Example
N.A.
The -symbol-info-file
Command
Synopsis
-symbol-info-file
Show the file for the symbol.
GDB Command
There's no equivalent GDB command. gdbtk
has
`gdb_find_file'.
Example
N.A.
The -symbol-info-function
Command
Synopsis
-symbol-info-function
Show which function the symbol lives in.
GDB Command
`gdb_get_function' in gdbtk
.
Example
N.A.
The -symbol-info-line
Command
Synopsis
-symbol-info-line
Show the core addresses of the code for a source line.
GDB Command
The corresponding GDB command is `info line'.
gdbtk
has the `gdb_get_line' and `gdb_get_file' commands.
Example
N.A.
The -symbol-info-symbol
Command
Synopsis
-symbol-info-symbol addr
Describe what symbol is at location addr.
GDB Command
The corresponding GDB command is `info symbol'.
Example
N.A.
The -symbol-list-functions
Command
Synopsis
-symbol-list-functions
List the functions in the executable.
GDB Command
`info functions' in GDB, `gdb_listfunc' and
`gdb_search' in gdbtk
.
Example
N.A.
The -symbol-list-lines
Command
Synopsis
-symbol-list-lines filename
Print the list of lines that contain code and their associated program addresses for the given source filename. The entries are sorted in ascending PC order.
GDB Command
There is no corresponding GDB command.
Example
(gdb) -symbol-list-lines basics.c ^done,lines=[{pc="0x08048554",line="7"},{pc="0x0804855a",line="8"}] (gdb)
The -symbol-list-types
Command
Synopsis
-symbol-list-types
List all the type names.
GDB Command
The corresponding commands are `info types' in GDB,
`gdb_search' in gdbtk
.
Example
N.A.
The -symbol-list-variables
Command
Synopsis
-symbol-list-variables
List all the global and static variable names.
GDB Command
`info variables' in GDB, `gdb_search' in gdbtk
.
Example
N.A.
The -symbol-locate
Command
Synopsis
-symbol-locate
GDB Command
`gdb_loc' in gdbtk
.
Example
N.A.
The -symbol-type
Command
Synopsis
-symbol-type variable
Show type of variable.
GDB Command
The corresponding GDB command is `ptype', gdbtk
has
`gdb_obj_variable'.
Example
N.A.
GDB/MI Target Manipulation Commands
The -target-attach
Command
Synopsis
-target-attach pid | file
Attach to a process pid or a file file outside of GDB.
GDB command
The corresponding GDB command is `attach'.
Example
N.A.
The -target-compare-sections
Command
Synopsis
-target-compare-sections [ section ]
Compare data of section section on target to the exec file. Without the argument, all sections are compared.
GDB Command
The GDB equivalent is `compare-sections'.
Example
N.A.
The -target-detach
Command
Synopsis
-target-detach
Disconnect from the remote target. There's no output.
GDB command
The corresponding GDB command is `detach'.
Example
(gdb) -target-detach ^done (gdb)
The -target-disconnect
Command
Synopsis
-target-disconnect
Disconnect from the remote target. There's no output.
GDB command
The corresponding GDB command is `disconnect'.
Example
(gdb) -target-disconnect ^done (gdb)
The -target-download
Command
Synopsis
-target-download
Loads the executable onto the remote target. It prints out an update message every half second, which includes the fields:
- `section'
- The name of the section.
- `section-sent'
- The size of what has been sent so far for that section.
- `section-size'
- The size of the section.
- `total-sent'
- The total size of what was sent so far (the current and the previous sections).
- `total-size'
- The size of the overall executable to download.
Each message is sent as status record (see section GDB/MI Output Syntax).
In addition, it prints the name and size of the sections, as they are downloaded. These messages include the following fields:
- `section'
- The name of the section.
- `section-size'
- The size of the section.
- `total-size'
- The size of the overall executable to download.
At the end, a summary is printed.
GDB Command
The corresponding GDB command is `load'.
Example
Note: each status message appears on a single line. Here the messages have been broken down so that they can fit onto a page.
(gdb) -target-download +download,{section=".text",section-size="6668",total-size="9880"} +download,{section=".text",section-sent="512",section-size="6668", total-sent="512",total-size="9880"} +download,{section=".text",section-sent="1024",section-size="6668", total-sent="1024",total-size="9880"} +download,{section=".text",section-sent="1536",section-size="6668", total-sent="1536",total-size="9880"} +download,{section=".text",section-sent="2048",section-size="6668", total-sent="2048",total-size="9880"} +download,{section=".text",section-sent="2560",section-size="6668", total-sent="2560",total-size="9880"} +download,{section=".text",section-sent="3072",section-size="6668", total-sent="3072",total-size="9880"} +download,{section=".text",section-sent="3584",section-size="6668", total-sent="3584",total-size="9880"} +download,{section=".text",section-sent="4096",section-size="6668", total-sent="4096",total-size="9880"} +download,{section=".text",section-sent="4608",section-size="6668", total-sent="4608",total-size="9880"} +download,{section=".text",section-sent="5120",section-size="6668", total-sent="5120",total-size="9880"} +download,{section=".text",section-sent="5632",section-size="6668", total-sent="5632",total-size="9880"} +download,{section=".text",section-sent="6144",section-size="6668", total-sent="6144",total-size="9880"} +download,{section=".text",section-sent="6656",section-size="6668", total-sent="6656",total-size="9880"} +download,{section=".init",section-size="28",total-size="9880"} +download,{section=".fini",section-size="28",total-size="9880"} +download,{section=".data",section-size="3156",total-size="9880"} +download,{section=".data",section-sent="512",section-size="3156", total-sent="7236",total-size="9880"} +download,{section=".data",section-sent="1024",section-size="3156", total-sent="7748",total-size="9880"} +download,{section=".data",section-sent="1536",section-size="3156", total-sent="8260",total-size="9880"} +download,{section=".data",section-sent="2048",section-size="3156", total-sent="8772",total-size="9880"} +download,{section=".data",section-sent="2560",section-size="3156", total-sent="9284",total-size="9880"} +download,{section=".data",section-sent="3072",section-size="3156", total-sent="9796",total-size="9880"} ^done,address="0x10004",load-size="9880",transfer-rate="6586", write-rate="429" (gdb)
The -target-exec-status
Command
Synopsis
-target-exec-status
Provide information on the state of the target (whether it is running or not, for instance).
GDB Command
There's no equivalent GDB command.
Example
N.A.
The -target-list-available-targets
Command
Synopsis
-target-list-available-targets
List the possible targets to connect to.
GDB Command
The corresponding GDB command is `help target'.
Example
N.A.
The -target-list-current-targets
Command
Synopsis
-target-list-current-targets
Describe the current target.
GDB Command
The corresponding information is printed by `info file' (among other things).
Example
N.A.
The -target-list-parameters
Command
Synopsis
-target-list-parameters
GDB Command
No equivalent.
Example
N.A.
The -target-select
Command
Synopsis
-target-select type parameters ...
Connect GDB to the remote target. This command takes two args:
- `type'
- The type of target, for instance `async', `remote', etc.
- `parameters'
- Device names, host names and the like. See section Commands for managing targets, for more details.
The output is a connection notification, followed by the address at which the target program is, in the following form:
^connected,addr="address",func="function name", args=[arg list]
GDB Command
The corresponding GDB command is `target'.
Example
(gdb) -target-select async /dev/ttya ^connected,addr="0xfe00a300",func="??",args=[] (gdb)
GDB/MI Thread Commands
The -thread-info
Command
Synopsis
-thread-info
GDB command
No equivalent.
Example
N.A.
The -thread-list-all-threads
Command
Synopsis
-thread-list-all-threads
GDB Command
The equivalent GDB command is `info threads'.
Example
N.A.
The -thread-list-ids
Command
Synopsis
-thread-list-ids
Produces a list of the currently known GDB thread ids. At the end of the list it also prints the total number of such threads.
GDB Command
Part of `info threads' supplies the same information.
Example
No threads present, besides the main process:
(gdb) -thread-list-ids ^done,thread-ids={},number-of-threads="0" (gdb)
Several threads:
(gdb) -thread-list-ids ^done,thread-ids={thread-id="3",thread-id="2",thread-id="1"}, number-of-threads="3" (gdb)
The -thread-select
Command
Synopsis
-thread-select threadnum
Make threadnum the current thread. It prints the number of the new current thread, and the topmost frame for that thread.
GDB Command
The corresponding GDB command is `thread'.
Example
(gdb) -exec-next ^running (gdb) *stopped,reason="end-stepping-range",thread-id="2",line="187", file="../../../devo/gdb/testsuite/gdb.threads/linux-dp.c" (gdb) -thread-list-ids ^done, thread-ids={thread-id="3",thread-id="2",thread-id="1"}, number-of-threads="3" (gdb) -thread-select 3 ^done,new-thread-id="3", frame={level="0",func="vprintf", args=[{name="format",value="0x8048e9c \"%*s%c %d %c\\n\""}, {name="arg",value="0x2"}],file="vprintf.c",line="31"} (gdb)
GDB/MI Tracepoint Commands
The tracepoint commands are not yet implemented.
GDB/MI Variable Objects
Motivation for Variable Objects in GDB/MI
For the implementation of a variable debugger window (locals, watched
expressions, etc.), we are proposing the adaptation of the existing code
used by Insight
.
The two main reasons for that are:
- It has been proven in practice (it is already on its second generation).
- It will shorten development time (needless to say how important it is now).
The original interface was designed to be used by Tcl code, so it was slightly changed so it could be used through GDB/MI. This section describes the GDB/MI operations that will be available and gives some hints about their use.
Note: In addition to the set of operations described here, we expect the GUI implementation of a variable window to require, at least, the following operations:
-gdb-show
output-radix
-stack-list-arguments
-stack-list-locals
-stack-select-frame
Introduction to Variable Objects in GDB/MI
The basic idea behind variable objects is the creation of a named object to represent a variable, an expression, a memory location or even a CPU register. For each object created, a set of operations is available for examining or changing its properties.
Furthermore, complex data types, such as C structures, are represented
in a tree format. For instance, the struct
type variable is the
root and the children will represent the struct members. If a child
is itself of a complex type, it will also have children of its own.
Appropriate language differences are handled for C, C++ and Java.
When returning the actual values of the objects, this facility allows
for the individual selection of the display format used in the result
creation. It can be chosen among: binary, decimal, hexadecimal, octal
and natural. Natural refers to a default format automatically
chosen based on the variable type (like decimal for an int
, hex
for pointers, etc.).
The following is the complete set of GDB/MI operations defined to access this functionality:
@multitable @columnfractions .4 .6
-var-create
@tab create a variable object
-var-delete
@tab delete the variable object and its children
-var-set-format
@tab set the display format of this variable
-var-show-format
@tab show the display format of this variable
-var-info-num-children
@tab tells how many children this object has
-var-list-children
@tab return a list of the object's children
-var-info-type
@tab show the type of this variable object
-var-info-expression
@tab print what this variable object represents
-var-show-attributes
@tab is this variable editable? does it exist here?
-var-evaluate-expression
@tab get the value of this variable
-var-assign
@tab set the value of this variable
-var-update
@tab update the variable and its children
In the next subsection we describe each operation in detail and suggest
how it can be used.
Description And Use of Operations on Variable Objects
The -var-create
Command
Synopsis
-var-create {name | "-"} {frame-addr | "*"} expressionThis operation creates a variable object, which allows the monitoring of a variable, the result of an expression, a memory cell or a CPU register. The name parameter is the string by which the object can be referenced. It must be unique. If `-' is specified, the varobj system will generate a string "varNNNNNN" automatically. It will be unique provided that one does not specify name on that format. The command fails if a duplicate name is found. The frame under which the expression should be evaluated can be specified by frame-addr. A `*' indicates that the current frame should be used. expression is any expression valid on the current language set (must not begin with a `*'), or one of the following:
- `*addr', where addr is the address of a memory cell
- `*addr-addr' -- a memory address range (TBD)
- `$regname' -- a CPU register name
Result
This operation returns the name, number of children and the type of the object created. Type is returned as a string as the ones generated by the GDB CLI:name="name",numchild="N",type="type"
The -var-delete
Command
Synopsis
-var-delete nameDeletes a previously created variable object and all of its children. Returns an error if the object name is not found.
The -var-set-format
Command
Synopsis
-var-set-format name format-specSets the output format for the value of the object name to be format-spec. The syntax for the format-spec is as follows:
format-spec ==> {binary | decimal | hexadecimal | octal | natural}
The -var-show-format
Command
Synopsis
-var-show-format nameReturns the format used to display the value of the object name.
format ==> format-spec
The -var-info-num-children
Command
Synopsis
-var-info-num-children nameReturns the number of children of a variable object name:
numchild=n
The -var-list-children
Command
Synopsis
-var-list-children [print-values] name@anchor{-var-list-children} Return a list of the children of the specified variable object and create variable objects for them, if they do not already exist. With a single argument or if print-values has a value for of 0 or
--no-values
, print only the names of the variables; if
print-values is 1 or --all-values
, also print their
values; and if it is 2 or --simple-values
print the name and
value for simple data types and just the name for arrays, structures
and unions.
Example
(gdb) -var-list-children n ^done,numchild=n,children=[{name=name, numchild=n,type=type},(repeats N times)] (gdb) -var-list-children --all-values n ^done,numchild=n,children=[{name=name, numchild=n,value=value,type=type},(repeats N times)]
The -var-info-type
Command
Synopsis
-var-info-type nameReturns the type of the specified variable name. The type is returned as a string in the same format as it is output by the GDB CLI:
type=typename
The -var-info-expression
Command
Synopsis
-var-info-expression nameReturns what is represented by the variable object name:
lang=lang-spec,exp=expressionwhere lang-spec is
{"C" | "C++" | "Java"}
.
The -var-show-attributes
Command
Synopsis
-var-show-attributes nameList attributes of the specified variable object name:
status=attr [ ( ,attr )* ]where attr is
{ { editable | noneditable } | TBD }
.
The -var-evaluate-expression
Command
Synopsis
-var-evaluate-expression nameEvaluates the expression that is represented by the specified variable object and returns its value as a string in the current format specified for the object:
value=valueNote that one must invoke
-var-list-children
for a variable
before the value of a child variable can be evaluated.
The -var-assign
Command
Synopsis
-var-assign name expressionAssigns the value of expression to the variable object specified by name. The object must be `editable'. If the variable's value is altered by the assign, the variable will show up in any subsequent
-var-update
list.
Example
(gdb) -var-assign var1 3 ^done,value="3" (gdb) -var-update * ^done,changelist=[{name="var1",in_scope="true",type_changed="false"}] (gdb)
The -var-update
Command
Synopsis
-var-update [print-values] {name | "*"}Update the value of the variable object name by evaluating its expression after fetching all the new values from memory or registers. A `*' causes all existing variable objects to be updated. The option print-values determines whether names and values, or just names are printed in the manner described for
@xref{-var-list-children
}.
Example
(gdb) -var-assign var1 3 ^done,value="3" (gdb) -var-update --all-values var1 ^done,changelist=[{name="var1",value="3",in_scope="true", type_changed="false"}] (gdb)
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