TCGETSID(3)            FreeBSD Library Functions Manual            TCGETSID(3)

NAME
     tcgetsid - get session ID associated with a controlling terminal

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/types.h>
     #include <termios.h>

     pid_t
     tcgetsid(int fd);

DESCRIPTION
     The tcgetsid() function returns the process group ID of the session
     leader for a controlling terminal specified by fd.

ERRORS
     If an error occurs, tcgetsid() returns -1 and the global variable errno
     is set to indicate the error, as follows:

     [EBADF]            The fd argument is not a valid file descriptor.

     [ENOTTY]           The calling process does not have a controlling
                        terminal or the underlying terminal device represented
                        by fd is not the controlling terminal.

SEE ALSO
     getsid(2), setsid(2), tcgetpgrp(3), tcsetsid(3)

STANDARDS
     The tcgetsid() function conforms to X/Open Portability Guide Issue 4,
     Version 2 ("XPG4.2").

FreeBSD 13.1-RELEASE-p6         April 15, 2008         FreeBSD 13.1-RELEASE-p6