isatty(3p) — Linux manual page

ISATTY(3P)              POSIX Programmer's Manual             ISATTY(3P)

PROLOG

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME

       isatty — test for a terminal device

SYNOPSIS

       #include <unistd.h>

       int isatty(int fildes);

DESCRIPTION

       The isatty() function shall test whether fildes, an open file
       descriptor, is associated with a terminal device.

RETURN VALUE

       The isatty() function shall return 1 if fildes is associated with
       a terminal; otherwise, it shall return 0 and may set errno to
       indicate the error.

ERRORS

       The isatty() function may fail if:

       EBADF  The fildes argument is not a valid open file descriptor.

       ENOTTY The file associated with the fildes argument is not a
              terminal.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The isatty() function does not necessarily indicate that a human
       being is available for interaction via fildes.  It is quite
       possible that non-terminal devices are connected to the
       communications line.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of POSIX.1‐2017, unistd.h(0p)

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                        ISATTY(3P)

Pages that refer to this page: unistd.h(0p), tty(1p)

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