getsid
GETSID(2)                  Linux Programmer's Manual                 GETSID(2)
NAME
       getsid - get session ID
SYNOPSIS
       #include <unistd.h>
       pid_t getsid(pid_t pid);
DESCRIPTION
       getsid(0)  returns  the  session  ID of the calling process.  getsid(p)
       returns the session ID of the process with process ID p.  (The  session
       ID  of  a  process  is the process group ID of the session leader.)  On
       error, (pid_t) -1 will be returned, and errno is set appropriately.
ERRORS
       EPERM  A process with process ID p exists, but it is not  in  the  same
              session as the current process, and the implementation considers
              this an error.
       ESRCH  No process with process ID p was found.
CONFORMING TO
       SVr4, POSIX 1003.1-2001.
NOTES
       Linux does not return EPERM.
       Linux has this system call since Linux 1.3.44.  There is  libc  support
       since libc 5.2.19.
       To  get  the  prototype  under  glibc,  define  both  _XOPEN_SOURCE and
       _XOPEN_SOURCE_EXTENDED, or use "#define _XOPEN_SOURCE n" for some inte-
       ger n larger than or equal to 500.
SEE ALSO
       getpgid(2), setsid(2)
Linux 2.5.0                       2001-12-17                         GETSID(2)