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

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.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────┬───────────────┬─────────┐
       │Interface Attribute     Value   │
       ├──────────┼───────────────┼─────────┤
       │isatty()  │ Thread safety │ MT-Safe │
       └──────────┴───────────────┴─────────┘

CONFORMING TO         top

       SVr4, 4.3BSD, POSIX.1-2001.

SEE ALSO         top

       fstat(2), ttyname(3)

COLOPHON         top

       This page is part of release 4.00 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       http://www.kernel.org/doc/man-pages/.

Linux                            2015-03-02                        ISATTY(3)