posix_getpgid
    (PHP 3>= 3.0.10, PHP 4 )
posix_getpgid -- Get process group id for job control
Description
int 
posix_getpgid ( int pid)
     Returns the process group identifier of the process
     pid.
    
     This is not a POSIX function, but is common on BSD and System V
     systems. If your system does not support this function at system
     level, this PHP function will always return FALSE.