SETPGID(2) BSD System Calls Manual SETPGID(2)NAME
setpgid, setpgrp — set process group
Standard C Library (libc, -lc)
setpgid(pid_t pid, pid_t pgrp);
setpgrp(pid_t pid, pid_t pgrp);
The setpgid() system call sets the process group of the specified process
pid to the specified pgrp. If pid is zero, then the call applies to the
If the affected process is not the invoking process, then it must be a
child of the invoking process, it must not have performed an exec(3)
operation, and both processes must be in the same session. The requested
process group ID must already exist in the session of the caller, or it
must be equal to the target process ID.
The setpgid() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The setpgrp() system call is identical to setpgid(), and is retained for
calling convention compatibility with historical versions of BSD.
The setpgid() system call will fail and the process group will not be
[EINVAL] The requested process group ID is not legal.
[ESRCH] The requested process does not exist.
[ESRCH] The target process is not the calling process or a
child of the calling process.
[EACCES] The requested process is a child of the calling
process, but it has performed an exec(3) operation.
[EPERM] The target process is a session leader.
[EPERM] The requested process group ID is not in the session
of the caller, and it is not equal to the process ID
of the target process.
The setpgid() system call is expected to conform to ISO/IEC 9945-1:1990
BSD February 8, 2004 BSD