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



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


NNAAMMEE
       isatty -- test for a terminal device

SSYYNNOOPPSSIISS
       #include <unistd.h>

       int isatty(int _f_i_l_d_e_s);

DDEESSCCRRIIPPTTIIOONN
       The _i_s_a_t_t_y() function shall test whether _f_i_l_d_e_s, an open file
       descriptor, is associated with a terminal device.

RREETTUURRNN VVAALLUUEE
       The _i_s_a_t_t_y() function shall return 1 if _f_i_l_d_e_s is associated with a
       terminal; otherwise, it shall return 0 and may set _e_r_r_n_o to indicate
       the error.

EERRRROORRSS
       The _i_s_a_t_t_y() function may fail if:

       EEBBAADDFF  The _f_i_l_d_e_s argument is not a valid open file descriptor.

       EENNOOTTTTYY The file associated with the _f_i_l_d_e_s argument is not a terminal.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

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

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       The Base Definitions volume of POSIX.1-2008, <<uunniissttdd..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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                  2013                            ISATTY(3)
