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GLOB(3) BSD Library Functions Manual GLOB(3)
NAME
glob, globfree -- generate pathnames matching a pattern
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <glob.h>
int
glob(const char *restrict pattern, int flags,
int (*errfunc)(const char *epath, int eerno),
glob_t *restrict pglob);
void
globfree(glob_t *pglob);
DESCRIPTION
The glob() function is a pathname generator that implements the rules for
file name pattern matching used by the shell.
The include file <glob.h> defines the structure type glob_t, which con-tains contains
tains at least the following fields:
typedef struct {
int gl_pathc; /* count of total paths so far */
int gl_matchc; /* count of paths matching pattern */
int gl_offs; /* reserved at beginning of gl_pathv */
int gl_flags; /* returned flags */
char **gl_pathv; /* list of paths matching pattern */
} glob_t;
The argument pattern is a pointer to a pathname pattern to be expanded.
The glob() argument matches all accessible pathnames against the pattern
and creates a list of the pathnames that match. In order to have access
to a pathname, glob() requires search permission on every component of a
path except the last and read permission on each directory of any file-name filename
name component of pattern that contains any of the special characters
`*', `?' or `['.
The glob() argument stores the number of matched pathnames into the
gl_pathc field, and a pointer to a list of pointers to pathnames into the
gl_pathv field. The first pointer after the last pathname is NULL. If
the pattern does not match any pathnames, the returned number of matched
paths is set to zero.
It is the caller's responsibility to create the structure pointed to by
pglob. The glob() function allocates other space as needed, including
the memory pointed to by gl_pathv.
The argument flags is used to modify the behavior of glob(). The value
of flags is the bitwise inclusive OR of any of the following values
defined in <glob.h>:
GLOB_APPEND Append pathnames generated to the ones from a previous
call (or calls) to glob(). The value of gl_pathc will
be the total matches found by this call and the previous
call(s). The pathnames are appended to, not merged with
the pathnames returned by the previous call(s). Between
calls, the caller must not change the setting of the
GLOB_DOOFFS flag, nor change the value of gl_offs when
GLOB_DOOFFS is set, nor (obviously) call globfree() for
pglob.
GLOB_DOOFFS Make use of the gl_offs field. If this flag is set,
gl_offs is used to specify how many NULL pointers to
prepend to the beginning of the gl_pathv field. In
other words, gl_pathv will point to gl_offs NULL point-ers, pointers,
ers, followed by gl_pathc pathname pointers, followed by
a NULL pointer.
GLOB_ERR Causes glob() to return when it encounters a directory
that it cannot open or read. Ordinarily, glob() contin-ues continues
ues to find matches.
GLOB_MARK Each pathname that is a directory that matches pattern
has a slash appended.
GLOB_NOCHECK If pattern does not match any pathname, then glob()
returns a list consisting of only pattern, with the num-ber number
ber of total pathnames set to 1, and the number of
matched pathnames set to 0. The effect of backslash
escaping is present in the pattern returned.
GLOB_NOESCAPE By default, a backslash (`\') character is used to
escape the following character in the pattern, avoiding
any special interpretation of the character. If
GLOB_NOESCAPE is set, backslash escaping is disabled.
GLOB_NOSORT By default, the pathnames are sorted in ascending ASCII
order; this flag prevents that sorting (speeding up
glob()).
The following values may also be included in flags, however, they are
non-standard extensions to IEEE Std 1003.2 (``POSIX.2'').
GLOB_ALTDIRFUNC The following additional fields in the pglob structure
have been initialized with alternate functions for glob
to use to open, read, and close directories and to get
stat information on names found in those directories.
void *(*gl_opendir)(const char * name);
struct dirent *(*gl_readdir)(void *);
void (*gl_closedir)(void *);
int (*gl_lstat)(const char *name, struct stat *st);
int (*gl_stat)(const char *name, struct stat *st);
This extension is provided to allow programs such as
restore(8) to provide globbing from directories stored
on tape.
GLOB_BRACE Pre-process the pattern string to expand `{pat,pat,...}'
strings like csh(1). The pattern `{}' is left unex-panded unexpanded
panded for historical reasons (and csh(1) does the same
thing to ease typing of find(1) patterns).
GLOB_MAGCHAR Set by the glob() function if the pattern included glob-bing globbing
bing characters. See the description of the usage of
the gl_matchc structure member for more details.
GLOB_NOMAGIC Is the same as GLOB_NOCHECK but it only appends the
pattern if it does not contain any of the special char-acters characters
acters ``*'', ``?'' or ``[''. GLOB_NOMAGIC is provided
to simplify implementing the historic csh(1) globbing
behavior and should probably not be used anywhere else.
GLOB_TILDE Expand patterns that start with `~' to user name home
directories.
GLOB_LIMIT Limit the total number of returned pathnames to the
value provided in gl_matchc (default ARG_MAX). This
option should be set for programs that can be coerced
into a denial of service attack via patterns that expand
to a very large number of matches, such as a long string
of `*/../*/..'.
If, during the search, a directory is encountered that cannot be opened
or read and errfunc is non-NULL, glob() calls (*errfunc)(path, errno).
This may be unintuitive: a pattern like `*/Makefile' will try to stat(2)
`foo/Makefile' even if `foo' is not a directory, resulting in a call to
errfunc. The error routine can suppress this action by testing for
ENOENT and ENOTDIR; however, the GLOB_ERR flag will still cause an imme-diate immediate
diate return when this happens.
If errfunc returns non-zero, glob() stops the scan and returns
GLOB_ABORTED after setting gl_pathc and gl_pathv to reflect any paths
already matched. This also happens if an error is encountered and
GLOB_ERR is set in flags, regardless of the return value of errfunc, if
called. If GLOB_ERR is not set and either errfunc is NULL or errfunc
returns zero, the error is ignored.
The globfree() function frees any space associated with pglob from a pre-vious previous
vious call(s) to glob().
RETURN VALUES
On successful completion, glob() returns zero. In addition, the fields
of pglob contain the values described below:
gl_pathc contains the total number of matched pathnames so far.
This includes other matches from previous invocations of
glob() if GLOB_APPEND was specified.
gl_matchc contains the number of matched pathnames in the current
invocation of glob().
gl_flags contains a copy of the flags argument with the bit
GLOB_MAGCHAR set if pattern contained any of the special
characters ``*'', ``?'' or ``['', cleared if not.
gl_pathv contains a pointer to a NULL-terminated list of matched
pathnames. However, if gl_pathc is zero, the contents of
gl_pathv are undefined.
If glob() terminates due to an error, it sets errno and returns one of
the following non-zero constants, which are defined in the include file
<glob.h>:
GLOB_NOSPACE An attempt to allocate memory failed, or if errno was 0
GLOB_LIMIT was specified in the flags and pglob->gl_matchc
or more patterns were matched.
GLOB_ABORTED The scan was stopped because an error was encountered and
either GLOB_ERR was set or (*errfunc)() returned non-zero.
GLOB_NOMATCH The pattern did not match a pathname and GLOB_NOCHECK was
not set.
The arguments pglob->gl_pathc and pglob->gl_pathv are still set as speci-fied specified
fied above.
EXAMPLES
A rough equivalent of `ls -l *.c *.h' can be obtained with the following
code:
glob_t g;
g.gl_offs = 2;
glob("*.c", GLOB_DOOFFS, NULL, &g);
glob("*.h", GLOB_DOOFFS | GLOB_APPEND, NULL, &g);
g.gl_pathv[0] = "ls";
g.gl_pathv[1] = "-l";
execvp("ls", g.gl_pathv);
CAVEATS
The glob() function will not match filenames that begin with a period
unless this is specifically requested (e.g., by ".*").
SEE ALSO
sh(1), fnmatch(3), regexp(3)
STANDARDS
The current implementation of the glob() function does not conform to
IEEE Std 1003.2 (``POSIX.2''). Collating symbol expressions, equivalence
class expressions and character class expressions are not supported.
The flags GLOB_ALTDIRFUNC, GLOB_BRACE, GLOB_LIMIT, GLOB_MAGCHAR,
GLOB_NOMAGIC, and GLOB_TILDE, and the fields gl_matchc and gl_flags are
extensions to the POSIX standard and should not be used by applications
striving for strict conformance.
HISTORY
The glob() and globfree() functions first appeared in 4.4BSD.
BUGS
Patterns longer than MAXPATHLEN may cause unchecked errors.
The glob() argument may fail and set errno for any of the errors speci-fied specified
fied for the library routines stat(2), closedir(3), opendir(3),
readdir(3), malloc(3), and free(3).
BSD September 1, 2004 BSD
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