getpgid - get the process group ID for a process
The getpgid() function shall return the process group ID of the process whose process ID is equal to pid. If pid is equal to 0, getpgid() shall return the process group ID of the calling process.
Upon successful completion, getpgid() shall return a process group ID. Otherwise, it shall return (pid_t)-1 and set errno to indicate the error.
The getpgid() function shall fail if:
- 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.
- There is no process with a process ID equal to pid.
The getpgid() function may fail if:
- The value of the pid argument is invalid.
exec(), fork(), getpgrp(), getpid(), getsid(), setpgid(), setsid(), the Base Definitions volume of IEEE Std 1003.1-2001, <unistd.h>
First released in Issue 4, Version 2.
Moved from X/OPEN UNIX extension to BASE.