170 lines
4.2 KiB
Groff
170 lines
4.2 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)putc.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd January 10, 2003
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.Dt PUTC 3
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.Os
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.Sh NAME
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.Nm fputc ,
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.Nm putc ,
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.Nm putc_unlocked ,
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.Nm putchar ,
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.Nm putchar_unlocked ,
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.Nm putw
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.Nd output a character or word to a stream
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft int
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.Fn fputc "int c" "FILE *stream"
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.Ft int
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.Fn putc "int c" "FILE *stream"
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.Ft int
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.Fn putc_unlocked "int c" "FILE *stream"
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.Ft int
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.Fn putchar "int c"
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.Ft int
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.Fn putchar_unlocked "int c"
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.Ft int
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.Fn putw "int w" "FILE *stream"
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.Sh DESCRIPTION
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The
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.Fn fputc
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function
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writes the character
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.Fa c
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(converted to an ``unsigned char'')
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to the output stream pointed to by
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.Fa stream .
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.Pp
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The
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.Fn putc
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macro acts essentially identically to
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.Fn fputc ,
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but is a macro that expands in-line.
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It may evaluate
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.Fa stream
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more than once, so arguments given to
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.Fn putc
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should not be expressions with potential side effects.
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.Pp
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The
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.Fn putchar
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function
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is identical to
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.Fn putc
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with an output stream of
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.Dv stdout .
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.Pp
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The
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.Fn putw
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function
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writes the specified
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.Vt int
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to the named output
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.Fa stream .
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.Pp
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The
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.Fn putc_unlocked
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and
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.Fn putchar_unlocked
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functions are equivalent to
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.Fn putc
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and
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.Fn putchar
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respectively,
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except that the caller is responsible for locking the stream
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with
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.Xr flockfile 3
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before calling them.
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These functions may be used to avoid the overhead of locking the stream
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for each character, and to avoid output being interspersed from multiple
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threads writing to the same stream.
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.Sh RETURN VALUES
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The functions,
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.Fn fputc ,
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.Fn putc ,
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.Fn putchar ,
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.Fn putc_unlocked
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and
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.Fn putchar_unlocked
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return the character written.
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If an error occurs, the value
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.Dv EOF
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is returned.
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The
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.Fn putw
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function
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returns 0 on success;
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.Dv EOF
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is returned if
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a write error occurs,
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or if an attempt is made to write a read-only stream.
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.Sh SEE ALSO
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.Xr ferror 3 ,
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.Xr flockfile 3 ,
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.Xr fopen 3 ,
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.Xr getc 3 ,
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.Xr putwc 3 ,
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.Xr stdio 3
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.Sh STANDARDS
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The functions
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.Fn fputc ,
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.Fn putc ,
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and
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.Fn putchar ,
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conform to
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.St -isoC .
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The
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.Fn putc_unlocked
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and
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.Fn putchar_unlocked
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functions conform to
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.St -p1003.1-2001 .
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A function
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.Fn putw
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function appeared in
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.At v6 .
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.Sh BUGS
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The size and byte order of an
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.Vt int
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varies from one machine to another, and
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.Fn putw
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is not recommended for portable applications.
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