NAME
setpgid, setpgrp
    — set process group
LIBRARY
library “libc”
SYNOPSIS
#include
    <unistd.h>
int
  
  setpgid(pid_t
    pid, pid_t
  pgrp);
int
  
  setpgrp(pid_t
    pid, pid_t
  pgrp);
DESCRIPTION
Setpgid()
  sets the process group of the specified process pid to
  the specified pgrp. If pid is
  zero, then the call applies to the current process. If
  pgrp is zero, then the process id of the process
  specified by pid is used instead.
If the invoker is not the super-user, then the affected process must have the same effective user-id as the invoker or be a descendant of the invoking process.
RETURN VALUES
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
    error.
COMPATIBILITY
Setpgrp() is identical to
    setpgid(), and is retained for calling convention
    compatibility with historical versions of BSD.
ERRORS
Setpgid() will fail and the process group
    will not be altered if:
- [EACCES]
- The value of the pid argument matches the process ID of a child process of the calling process, and the child process has successfully executed one of the exec(3) functions.
- [EINVAL]
- The value of the pgrp is not legal (less than zero).
- [EPERM]
- The effective user ID of the requested process is different from that of the caller and the process is not a descendant of the calling process.
- [ESRCH]
- The value of the pid argument does not match the process ID of the calling process or of a child process of the calling process.
SEE ALSO
STANDARDS
The setpgid() function call is expected to
    conform to IEEE Std 1003.1-1990
    (“POSIX.1”).