NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON

The Linux Programming Interface

ISATTY(3)                     Linux Programmer's Manual                     ISATTY(3)

NAME         top

       isatty - test whether a file descriptor refers to a terminal

SYNOPSIS         top

       #include <unistd.h>

       int isatty(int fd);

DESCRIPTION         top

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

RETURN VALUE         top

       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         top

       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         top

       SVr4, 4.3BSD, POSIX.1-2001.

SEE ALSO         top

       fstat(2), ttyname(3)

COLOPHON         top

       This page is part of release 3.32 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/.

Linux                                 2008-12-03                            ISATTY(3)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface