isatty()

Test to see if a file descriptor is associated with a terminal

Synopsis:

#include <unistd.h>

int isatty( int fildes );

Library:

libc

Description:

The isatty() function allows the calling process to determine if the file descriptor fildes is associated with a terminal.

Returns:

0

The fildes file descriptor doesn't refer to a terminal.

1

The fildes file descriptor refers to a terminal.

Examples:

/*
 * The following program exits with a status of
 * EXIT_SUCCESS if stderr is a tty; otherwise,
 * EXIT_FAILURE
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main( void )
  {
    return( isatty( 3 ) ? EXIT_SUCCESS : EXIT_FAILURE );
  }

Classification:

POSIX 1003.1

See also:

open()