setpgid(S)

setpgid -- set process group ID

Synopsis

   #include <sys/types.h>
   #include <unistd.h>
   
   int setpgid(pid_t pid, pid_t pgid);

Description

setpgid sets the process group ID of the process with ID pid to pgid. If pgid is equal to pid, the process becomes a process group leader. If pgid is not equal to pid, the process becomes a member of an existing process group.

If pid is equal to 0, the process ID of the calling process is used. If pgid is equal to 0, the process specified by pid becomes a process group leader.

Return values

On success, setpgid returns 0. On failure, setpgid returns -1 and sets errno to identify the error.

Errors

In the following conditions, setpgid fails and sets errno to:

EACCES: pid matches the process ID of a child process of the calling process and the child process has successfully executed an exec(S) function.
EBUSY: pgid is associated with another process group.
EINVAL: pgid is less than (pid_t) 0, or greater than or equal to {PID_MAX}.
EINVAL: The calling process has a controlling terminal that does not support job control.
EPERM: The process indicated by the pid argument is a session leader.
EPERM: pid matches the process ID of a child process of the calling process and the child process is not in the same session as the calling process.
EPERM: pgid does not match the process ID of the process indicated by the pid argument and there is no process with a process group ID that matches pgid in the same session as the calling process.
ESRCH: pid does not match the process ID of the calling process or of a child process of the calling process.

References

exec(S), exit(S), fork(S), getpid(S), setsid(S)

Notices

Considerations for threads programming

This ID number is an attribute of the containing process and is shared by sibling threads.