tcgetsid - get the process group ID for the session leader for the controlling terminal
The tcgetsid() function shall obtain the process group ID of the session for which the terminal specified by fildes is the controlling terminal.
Upon successful completion, tcgetsid() shall return the process group ID associated with the terminal. Otherwise, a value of (pid_t)-1 shall be returned and errno set to indicate the error.
The tcgetsid() function shall fail if:
- The fildes argument is not a valid file descriptor.
- The calling process does not have a controlling terminal, or the file is not the controlling terminal.
The Base Definitions volume of IEEE Std 1003.1-2001, <termios.h>
First released in Issue 4, Version 2.
Moved from X/OPEN UNIX extension to BASE.
The [EACCES] error has been removed from the list of mandatory errors, and the description of [ENOTTY] has been reworded.