mirror of https://github.com/mkerrisk/man-pages
72 lines
2.0 KiB
Groff
72 lines
2.0 KiB
Groff
.\" Copyright 2008, Linux Foundation, written by Michael Kerrisk
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.\" <mtk.manpages@gmail.com>
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\" %%%LICENSE_END
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.\"
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.TH ISATTY 3 2014-01-27 "Linux" "Linux Programmer's Manual"
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.SH NAME
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isatty \- test whether a file descriptor refers to a terminal
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.SH SYNOPSIS
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.nf
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.B #include <unistd.h>
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.sp
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.BI "int isatty(int " fd );
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.fi
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.SH DESCRIPTION
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The
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.BR isatty ()
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function tests whether
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.I fd
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is an open file descriptor referring to a terminal.
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.SH RETURN VALUE
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.BR isatty ()
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returns 1 if
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.I fd
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is an open file descriptor referring to a terminal;
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otherwise 0 is returned, and
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.I errno
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is set to indicate the error.
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.SH ERRORS
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.TP
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.B EBADF
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.I fd
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is not a valid file descriptor.
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.TP
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.B EINVAL
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.I fd
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refers to a file other than a terminal.
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POSIX.1-2001 specifies the error
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.BR ENOTTY
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.\" FIXME . File a bug for this?
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for this case.
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.SH ATTRIBUTES
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.SS Multithreading (see pthreads(7))
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The
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.BR isatty ()
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function is thread-safe.
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.SH CONFORMING TO
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SVr4, 4.3BSD, POSIX.1-2001.
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.SH SEE ALSO
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.BR fstat (2),
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.BR ttyname (3)
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