The session ID of the process identified by
Fa pid
is returned by
getsid (.);
If
Fa pid
is zero,
getsid ();
returns the session ID of the current process.
RETURN VALUES
Upon successful completion, the
getsid ();
system call
returns the session ID of
the specified process; otherwise, it returns a value of -1 and
sets errno to indicate an error.
ERRORS
The
getsid ();
system call
will succeed unless:
Bq Er ESRCH
if there is no process with a process ID equal to
Fa pid .
Note that an implementation may restrict this system call to
processes within the same session ID as the calling process.
