Process management

Collaboration diagram for Process management:

Functions
int	vlc_spawn (pid_t *pid, const char *file, const int *fdv, const char *const *argv)
	Spawn a child process (by file name).
int	vlc_spawnp (pid_t *pid, const char *path, const int *fdv, const char *const *argv)
	Spawn a child process.
int	vlc_waitpid (pid_t pid)
	Waits for a child process.

Detailed Description

Function Documentation

vlc_spawn()

int vlc_spawn	(	pid_t *	pid,
		const char *	file,
		const int *	fdv,
		const char *const *	argv
	)

Spawn a child process (by file name).

This function creates a child process. For all practical purposes, it is identical to vlc_spawnp(), with one exception: vlc_spawn() does not look for the executable file name in the OS-defined search path. Instead the file name must be absolute.

Parameters

pid	storage space for the child process identifier [OUT]
file	executable file path [IN]
fdv	file descriptor array [IN]
argv	NULL-terminated array of command line arguments [IN]

Returns

0 on success or a standard error code on failure

vlc_spawnp()

int vlc_spawnp	(	pid_t *	pid,
		const char *	path,
		const int *	fdv,
		const char *const *	argv
	)

Spawn a child process.

This function creates a child process. The created process will run with the same environment and privileges as the calling process.

An array of file descriptors must be provided for the child process:

• fdv[0] is the standard input (or -1 for nul input),
• fdv[1] is the standard output (or -1 for nul output),
• fdv[2] is the standard error (or -1 to ignore). The array must have at least 4 elements and be terminated by -1. Some platforms will ignore file descriptors other than the three standard ones, so those should not be used in code intended to be portable.

vlc_waitpid() must be called to collect outstanding system resources after the child process terminates.

Parameters

pid	storage space for the child process identifier [OUT]
path	executable path [IN]
fdv	file descriptor array [IN]
argv	NULL-terminated array of command line arguments [IN]

Returns

0 on success or a standard error code on failure

Referenced by vlc_getProxyUrl().

vlc_waitpid()

int vlc_waitpid

(

pid_t

pid

)

Waits for a child process.

This function waits until a child process created by vlc_spawn() or vlc_spawnp() has completed and releases any associated system resource.

Parameters

pid	process identifier as returned by vlc_spawn() or vlc_spawnp()

Returns

If the process terminates cleanly, this function returns the exit code of the process. Otherwise, it returns an implementation-defined value that is not a valid exit code.

References vlc_assert_unreachable.

Referenced by vlc_getProxyUrl().