NAME

       getpgid - get the process group ID for a process

SYNOPSIS

       #include <unistd.h>

       pid_t getpgid(pid_t pid);

DESCRIPTION

       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.

RETURN VALUE

       Upon successful completion, getpgid() shall return a process group ID. Otherwise, it shall
       return (pid_t)-1 and set errno to indicate the error.

ERRORS

       The getpgid() function shall 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.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       exec() , fork() , getpgrp() , getpid() , getsid()  ,  setpgid()  ,  setsid()  ,  the  Base
       Definitions volume of IEEE Std 1003.1-2001, <unistd.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .