This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical  and  Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE  and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                      TCGETSID(3POSIX)

       The tcgetsid() function shall obtain the process group ID of the session for which the terminal specified
       by fildes is the controlling terminal.

       The tcgetsid() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       ENOTTY The calling process does not have a controlling terminal, or  the  file  is  not  the  controlling
              terminal.

       Thefollowingsectionsareinformative.

       None.

       None.

       tcgetsid — get the process group ID for the session leader for the controlling terminal

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

       None.

       Upon  successful  completion, tcgetsid() shall return the process group ID of the session associated with
       the terminal. Otherwise, a value of -1 shall be returned and errno set to indicate the error.

       The Base Definitions volume of POSIX.1‐2017, <termios.h>

       #include <termios.h>

       pid_t tcgetsid(int fildes);