(PHP 3 >= 3.0.10, PHP 4, PHP 5)
posix_getsid -- Get the current sid of the process
( int pid )
Return the sid of the process pid. If
pid is 0, the sid of the current process
This is not a POSIX function, but is common on System V systems.
If your system does not support this function at system level,
this PHP function will always return FALSE.