mirror of https://github.com/mkerrisk/man-pages
103 lines
2.5 KiB
Groff
103 lines
2.5 KiB
Groff
.\" Copyright (C) 2014 Michael Kerrisk <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.\" manual page may be incorrect or out-of-date.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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.\" 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 ISFDTYPE 3 2020-08-13 "Linux" "Linux Programmer's Manual"
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.SH NAME
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isfdtype \- test file type of a file descriptor
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.SH SYNOPSIS
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.nf
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.B #include <sys/stat.h>
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.B #include <sys/socket.h>
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.PP
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.BI "int isfdtype(int " fd ", int " fdtype );
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.fi
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.PP
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.PP
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.BR isfdtype ():
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.ad l
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.RS 4
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.PD 0
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.TP 4
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Since glibc 2.20:
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_DEFAULT_SOURCE
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.TP 4
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Before glibc 2.20:
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_BSD_SOURCE || _SVID_SOURCE
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.PD
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.RE
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.ad b
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.SH DESCRIPTION
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The
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.BR isfdtype ()
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function tests whether the file descriptor
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.I fd
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refers to a file of type
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.IR fdtype .
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The
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.I fdtype
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argument specifies one of the
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.B S_IF*
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constants defined in
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.I <sys/stat.h>
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and documented in
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.BR stat (2)
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(e.g.,
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.BR S_IFREG ).
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.SH RETURN VALUE
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The
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.BR isfdtype ()
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function returns 1 if the file descriptor
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.I fd
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is of type
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.IR fdtype
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and 0 if it is not.
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On error, -1 is returned and
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.I errno
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is set to indicate the cause.
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.SH ERRORS
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The
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.BR isfdtype ()
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function can fail with any of the same errors as
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.BR fstat (3).
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.SH CONFORMING TO
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The
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.BR isfdtype ()
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function is not specified in any standard,
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but did appear in the draft POSIX.1g standard.
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It is present on OpenBSD and Tru64 UNIX
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(where the required header file in both cases is just
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.IR <sys/stat.h> ,
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as shown in the POSIX.1g draft),
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and possibly other systems.
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.SH NOTES
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Portable applications should use
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.BR fstat (3)
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instead.
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.SH SEE ALSO
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.BR fstat (3)
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