path: root/man3/unlocked_stdio.3

.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.TH UNLOCKED_STDIO 3  2017-09-15 "" "Linux Programmer's Manual"
.SH NAME
getc_unlocked, getchar_unlocked, putc_unlocked,
putchar_unlocked \- nonlocking stdio functions
.SH SYNOPSIS
.nf
.B #include <stdio.h>
.PP
.BI "int getc_unlocked(FILE *" stream );
.B "int getchar_unlocked(void);"
.BI "int putc_unlocked(int " c ", FILE *" stream );
.BI "int putchar_unlocked(int " c );
.PP
.BI "void clearerr_unlocked(FILE *" stream );
.BI "int feof_unlocked(FILE *" stream );
.BI "int ferror_unlocked(FILE *" stream );
.BI "int fileno_unlocked(FILE *" stream );
.BI "int fflush_unlocked(FILE *" stream );
.BI "int fgetc_unlocked(FILE *" stream );
.BI "int fputc_unlocked(int " c ", FILE *" stream );
.BI "size_t fread_unlocked(void *" ptr ", size_t " size ", size_t " n ,
.BI "                      FILE *" stream );
.BI "size_t fwrite_unlocked(const void *" ptr ", size_t " size ", size_t " n ,
.BI "                      FILE *" stream );
.PP
.BI "char *fgets_unlocked(char *" s ", int " n ", FILE *" stream );
.BI "int fputs_unlocked(const char *" s ", FILE *" stream );

.B #include <wchar.h>
.PP
.BI "wint_t getwc_unlocked(FILE *" stream );
.B "wint_t getwchar_unlocked(void);"
.BI "wint_t fgetwc_unlocked(FILE *" stream );
.BI "wint_t fputwc_unlocked(wchar_t " wc ", FILE *" stream );
.BI "wint_t putwc_unlocked(wchar_t " wc ", FILE *" stream );
.BI "wint_t putwchar_unlocked(wchar_t " wc );
.BI "wchar_t *fgetws_unlocked(wchar_t *" ws ", int " n ", FILE *" stream );
.BI "int fputws_unlocked(const wchar_t *" ws ", FILE *" stream );
.fi
.PP
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.ad l
.RE
.PP
.BR getc_unlocked (),
.BR getchar_unlocked (),
.BR putc_unlocked (),
.BR putchar_unlocked ():
.RS 4
/* Since glibc 2.24: */ _POSIX_C_SOURCE\ >=\ 199309L
    || /* Glibc versions <= 2.23: */ _POSIX_C_SOURCE
    || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
.RE
.PP
.BR clearerr_unlocked (),
.BR feof_unlocked (),
.BR ferror_unlocked (),
.BR fileno_unlocked (),
.BR fflush_unlocked (),
.BR fgetc_unlocked (),
.BR fputc_unlocked (),
.BR fread_unlocked (),
.BR fwrite_unlocked ():
.RS 4
/* Glibc since 2.19: */ _DEFAULT_SOURCE
    || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
.RE
.PP
.BR fgets_unlocked (),
.BR fputs_unlocked (),
.BR getwc_unlocked (),
.BR getwchar_unlocked (),
.BR fgetwc_unlocked (),
.BR fputwc_unlocked (),
.BR putwchar_unlocked (),
.BR fgetws_unlocked (),
.BR fputws_unlocked ():
.RS 4
_GNU_SOURCE
.RE
.ad b
.SH DESCRIPTION
Each of these functions has the same behavior as its counterpart
without the "_unlocked" suffix, except that they do not use locking
(they do not set locks themselves, and do not test for the presence
of locks set by others) and hence are thread-unsafe.
See
.BR flockfile (3).
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.TS
allbox;
lbw20 lb lb
l l l.
Interface	Attribute	Value
T{
.BR getc_unlocked (),
.BR putc_unlocked (),
.BR clearerr_unlocked (),
.BR fflush_unlocked (),
.BR fgetc_unlocked (),
.BR fputc_unlocked (),
.BR fread_unlocked (),
.BR fwrite_unlocked (),
.BR fgets_unlocked (),
.BR fputs_unlocked (),
.BR getwc_unlocked (),
.BR fgetwc_unlocked (),
.BR fputwc_unlocked (),
.BR putwc_unlocked (),
.BR fgetws_unlocked (),
.BR fputws_unlocked ()
T}	Thread safety	MT-Safe race:stream
T{
.BR getchar_unlocked (),
.BR getwchar_unlocked ()
T}	Thread safety	MT-Unsafe race:stdin
T{
.BR putchar_unlocked (),
.BR putwchar_unlocked ()
T}	Thread safety	MT-Unsafe race:stdout
T{
.BR feof_unlocked (),
.BR ferror_unlocked (),
.BR fileno_unlocked ()
T}	Thread safety	MT-Safe
.TE
.ad
.SH CONFORMING TO
The four functions
.BR getc_unlocked (),
.BR getchar_unlocked (),
.BR putc_unlocked (),
.BR putchar_unlocked ()
are in POSIX.1-2001 and POSIX.1-2008.
.PP
The nonstandard
.BR *_unlocked ()
variants occur on a few UNIX systems, and are available in recent glibc.
.\" E.g., in HP-UX 10.0. In HP-UX 10.30 they are called obsolescent, and
.\" moved to a compatibility library.
.\" Available in HP-UX 10.0: clearerr_unlocked, fclose_unlocked,
.\" feof_unlocked, ferror_unlocked, fflush_unlocked, fgets_unlocked,
.\" fgetwc_unlocked, fgetws_unlocked, fileno_unlocked, fputs_unlocked,
.\" fputwc_unlocked, fputws_unlocked, fread_unlocked, fseek_unlocked,
.\" ftell_unlocked, fwrite_unlocked, getc_unlocked, getchar_unlocked,
.\" getw_unlocked, getwc_unlocked, getwchar_unlocked, putc_unlocked,
.\" putchar_unlocked, puts_unlocked, putws_unlocked, putw_unlocked,
.\" putwc_unlocked, putwchar_unlocked, rewind_unlocked, setvbuf_unlocked,
.\" ungetc_unlocked, ungetwc_unlocked.
They should probably not be used.
.SH SEE ALSO
.BR flockfile (3),
.BR stdio (3)
.SH COLOPHON
This page is part of release 5.09 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.