Interprocess Communication

Tools for managing interprocess communication (IPC)

Modules
	Message Queues
	Shared Memory

Files
file	processInterface.hpp
	Process interface facilities.
file	sharedMemSegment.hpp
	Declarations for the mxlib shared memory facility.
file	processInterface.cpp
	Process interface facilities.
file	sharedMemSegment.cpp
	Definitions for the mxlib shared memory facility.

Functions
int	mx::ipc::command_response (const char *cmd, char *resp, size_t respsz)
	Run a process and copy the output to a string. More...
int	mx::ipc::runCommand (int &retVal, std::vector< std::string > &commandOutput, std::vector< std::string > &commandStderr, const std::vector< std::string > &commandList)
	Runs a command (with parameters) passed in using fork/exec. More...

Function Documentation

command_response()

int mx::ipc::command_response	(	const char *	cmd,
		char *	resp,
		size_t	respsz
	)

Run a process and copy the output to a string.

Uses popen, so the attendant precautions about privileges apply.

Parameters

cmd	is the command to run
resp	is the string to copy the response to.
respsz	is the available size of the string.

Return values

0	on success
-1	on error

Definition at line 43 of file processInterface.cpp.

runCommand()

int mx::ipc::runCommand	(	int &	retVal,
		std::vector< std::string > &	commandOutput,
		std::vector< std::string > &	commandStderr,
		const std::vector< std::string > &	commandList
	)

Runs a command (with parameters) passed in using fork/exec.

A new process is fork()-ed, and the child runs execvp with command provided. The output of the process is captured in commandOutput, and error messages in commandStderr.

The process return value in retVal is only meaningful if this function returns 0.

If this function returns -1, the last entry in commandStderr will contain a message, and errno may be useful.

Returns

0 on success

-1 on error

Parameters

[out]	retVal	the return value of the process. Only meaningful if this returns 0.
[out]	commandOutput	the output, line by line. If an error, first entry contains the message.
[out]	commandStderr	the output of stderr.
[in]	commandList	command to be run, with one entry per command line word

Definition at line 71 of file processInterface.cpp.

Referenced by mx::sys::gitRepo::getGitFileState(), mx::sys::gitRepo::getGitHash(), mx::sys::gitRepo::getGitModified(), and mx::sys::gitRepo::getGitName().