NAME

getpid, getpgrp, getppid, getpgid - get process, process group, and parent process IDs

SYNOPSIS

#include <unistd.h>

pid_t getpid(void);
pid_t getpgrp(void);
pid_t getppid(void);
pid_t getpgid(pid_t pid);

DESCRIPTION

getpid( ) returns the process ID of the calling process.

getpgrp( ) returns the process group ID of the calling process.

getppid( ) returns the parent process ID of the calling process.

getpgid( ) returns the process group ID of the process whose process ID is equal to pid, or the process group ID of the calling process, if pid is equal to 0.

RETURN VALUES

Upon successful completion, all return the process group ID .On failure, getpgid( ) returns a value of (pid_t) -1 and sets errno to indicate the error.

ERRORS

The getpgid( ) function will fail if:

EPERM

The process whose process ID is equal to pid is not in the same session as the calling process, and the implementation does not allow access to the process group ID of that process from the calling process.

ESRCH

There is no process with a process ID equal to pid.

The getpgid( ) function may fail if:

EINVAL

The value of the pid argument is invalid.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
MT-Level	Async-Signal-Safe

SEE ALSO

intro(2), exec(2), fork(2), getsid(2), setpgid(2), setpgrp(2), setsid(2), signal(3C), attributes(5)