tcgetsid

Synopsis

#include <termios.h>

pid_t tcgetsid(int fildes);

Status

Implemented

Conformance

IEEE Std 1003.1-2017

Description

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.

Return value

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.

Errors

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.

• EINVAL - The file associated with fildes is not a terminal, and the server handling it reports unsupported requests with EINVAL (see POSIX deviations).

POSIX deviations

If the file associated with fildes is not a terminal, the error reported by tcgetsid() depends on the server handling the file. The function is implemented on top of ioctl(), and the kernel forwards every request to the server without checking the type of the file. Servers that do not handle terminal requests report them either with ENOTTY (for example files in jffs2) or with EINVAL (for example pipes and files in dummyfs).