February 13, 1998 TCGETSID 3

### NAME

tcgetsid - get session ID associated with a controlling terminal

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```pid_t` tcgetsid(```int fd`)

### DESCRIPTION

The tcgetsid function returns the value of the session ID associated with the specified controlling terminal device. The session ID is defined as the process group ID of the session leader.

### 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)

### STANDARDS

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