NAME¶

isatty - test whether a file descriptor refers to a terminal

SYNOPSIS¶

#include <unistd.h>

int isatty(int fd);

DESCRIPTION¶

The isatty() function tests whether fd is an open file descriptor referring to a terminal.

RETURN VALUE¶

isatty() returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned, and errno is set to indicate the error.

ERRORS¶

EBADF

fd is not a valid file descriptor.

EINVAL

fd refers to a file other than a terminal. POSIX.1-2001 specifies the error ENOTTY for this case.

CONFORMING TO¶

SVr4, 4.3BSD, POSIX.1-2001.

SEE ALSO¶

fstat(2), ttyname(3)

COLOPHON¶

This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.