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Inside Macintosh: Interapplication Communication /

Chapter 11 - Program-to-Program Communications Toolbox / PPC Toolbox Reference

PPC Toolbox Routines / Obtaining a List of Ports

IPCListPorts

Use the IPCListPorts function to generate a list of existing ports without displaying a dialog box.

FUNCTION IPCListPorts (pb: IPCListPortsPBPtr; 
                       async: Boolean): OSErr; 

pb

A pointer to an IPCListPorts parameter block.

async

A value that specifies whether the function is to be executed asynchronously (TRUE) or synchronously (FALSE).

-->	ioCompletion	PPCCompProcPtr	Address of a completion routine
<--	ioResult	OSErr	Result code
-->	startIndex	Integer	Index to the port entry list
-->	requestCount	Integer	Number of port names requested
<--	actualCount	Integer	Number of port names returned
-->	portName	PPCPortPtr	Pointer to a PPCPortRec
-->	locationName	LocationNamePtr	Pointer to a LocationNameRec
-->	bufferPtr	PortInfoArrayPtr	Pointer to an array of PortInfoRec

DESCRIPTION

If your application calls the IPCListPorts function asynchronously, you must specify in the ioCompletion field either the address of a completion routine or NIL. If you set ioCompletion to NIL, you should poll the ioResult field of the PPC parameter block (from your application's main event loop) to determine whether the PPC Toolbox has completed the requested operation. A value in the ioResult field other than 1 indicates that the call is complete. Note that it is unsafe to poll the ioResult field at interrupt time since the PPC Toolbox may be in the process of completing a call. See "PPC Toolbox Calling Conventions" beginning on page 11-14 for detailed information.

If you call the IPCListPorts function asynchronously, you must not change any of the fields in the parameter block until the call completes. The port name, location name, and buffer pointed to by IPCListPortsPBRec are owned by the PPC Toolbox until the call completes. These objects must not be deallocated or moved in memory while the call is in progress.

The startIndex field specifies the index to the list of ports on the remote machine from which the PPC Toolbox begins to get the list. In most cases, you'll want to start at the beginning, so set the startIndex field to 0. The requestCount field specifies the maximum number of port information records that can fit into your buffer.

The actualCount field returns the actual number of entries returned. Your program can use the IPCListPorts function repeatedly to obtain the entire list of ports. Ports that are not visible to the network are not included in the ports listing on a remote machine. (If you specify FALSE for the networkVisible field in the PPCOpen function, the port is not included in the listing of available ports across a network.)

The portName field must contain a pointer to a PPC port record that specifies which PPC ports to list. You can specify particular values in the PPC port record or you can use an equal sign (=) in the name or the portTypeStr fields as a wildcard to match all port names or port types.

The locationName field should contain a pointer to a location name record that designates the computer that contains the PPC ports you want returned. If the locationKindSelector field in the location name record is ppcNoLocation or if the locationName pointer is NIL, then the location is the local machine. If the locationKindSelector field in the location name record is ppcNBPLocation, then the location is a remote machine designated by the location name record's nbpEntity field.

The IPCListPorts function returns an array (list) of port information records in the area of memory pointed to by bufferPtr. Make sure that the buffer pointed to by the bufferPtr field is at least sizeof(PortInfoRec) * requestCount.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the IPCListPorts function are

Trap macro	Selector
_PPC	$000A

The registers on entry and exit for this routine are

Registers on entry
A0	Pointer to a parameter block
D0	Selector code

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
notInitErr	-900	PPC Toolbox has not been initialized yet
nameTypeErr	-902	Invalid or inappropriate locationKindSelector in location name
noGlobalsErr	-904	System unable to allocate memory, critical error
localOnlyErr	-905	Network activity is currently disabled
sessTableErr	-907	PPC Toolbox is unable to create a session
noResponseErr	-915	Unable to contact application
badPortNameErr	-919	PPC port record is invalid
networkErr	-925	An error has occurred in the network
badLocNameErr	-931	Location name is invalid

SEE ALSO

For an example of the use of the IPCListPorts function, see Listing 11-5 on page 11-28.