171 lines
4.3 KiB
Groff
171 lines
4.3 KiB
Groff
.\" $NetBSD: getc.3,v 1.12 2003/08/07 16:43:26 agc Exp $
|
|
.\"
|
|
.\" Copyright (c) 1990, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to Berkeley by
|
|
.\" Chris Torek and the American National Standards Committee X3,
|
|
.\" on Information Processing Systems.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)getc.3 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd April 25, 2001
|
|
.Dt GETC 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm fgetc ,
|
|
.Nm getc ,
|
|
.Nm getchar ,
|
|
.Nm getc_unlocked ,
|
|
.Nm getchar_unlocked ,
|
|
.Nm getw
|
|
.Nd get next character or word from input stream
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In stdio.h
|
|
.Ft int
|
|
.Fn fgetc "FILE *stream"
|
|
.Ft int
|
|
.Fn getc "FILE *stream"
|
|
.Ft int
|
|
.Fn getchar
|
|
.Ft int
|
|
.Fn getc_unlocked "FILE *stream"
|
|
.Ft int
|
|
.Fn getchar_unlocked
|
|
.Ft int
|
|
.Fn getw "FILE *stream"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn fgetc
|
|
function
|
|
obtains the next input character (if present) from the stream pointed at by
|
|
.Fa stream ,
|
|
or the next character pushed back on the stream via
|
|
.Xr ungetc 3 .
|
|
.Pp
|
|
The
|
|
.Fn getc
|
|
function
|
|
acts essentially identically to
|
|
.Fn fgetc ,
|
|
but is a macro that expands in-line.
|
|
.Pp
|
|
The
|
|
.Fn getchar
|
|
function
|
|
is equivalent to:
|
|
getc with the argument stdin.
|
|
.Pp
|
|
The
|
|
.Fn getc_unlocked
|
|
and
|
|
.Fn getchar_unlocked
|
|
functions provide functionality identical to that of
|
|
.Fn getc
|
|
and
|
|
.Fn getchar ,
|
|
respectively, but do not perform implicit locking of the streams they
|
|
operate on.
|
|
In multi-threaded programs they may be used
|
|
.Em only
|
|
within a scope in which the stream
|
|
has been successfully locked by the calling thread using either
|
|
.Xr flockfile 3
|
|
or
|
|
.Xr ftrylockfile 3 ,
|
|
and may later be released using
|
|
.Xr funlockfile 3 .
|
|
.Pp
|
|
The
|
|
.Fn getw
|
|
function
|
|
obtains the next
|
|
.Em int
|
|
(if present)
|
|
from the stream pointed at by
|
|
.Fa stream .
|
|
.Sh RETURN VALUES
|
|
If successful, these routines return the next requested object
|
|
from the
|
|
.Fa stream .
|
|
If the stream is at end-of-file or a read error occurs,
|
|
the routines return
|
|
.Dv EOF .
|
|
The routines
|
|
.Xr feof 3
|
|
and
|
|
.Xr ferror 3
|
|
must be used to distinguish between end-of-file and error.
|
|
If an error occurs, the global variable
|
|
.Va errno
|
|
is set to indicate the error.
|
|
The end-of-file condition is remembered, even on a terminal, and all
|
|
subsequent attempts to read will return
|
|
.Dv EOF
|
|
until the condition is cleared with
|
|
.Xr clearerr 3 .
|
|
.Sh SEE ALSO
|
|
.Xr ferror 3 ,
|
|
.Xr flockfile 3 ,
|
|
.Xr fopen 3 ,
|
|
.Xr fread 3 ,
|
|
.Xr ftrylockfile 3 ,
|
|
.Xr funlockfile 3 ,
|
|
.Xr putc 3 ,
|
|
.Xr ungetc 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn fgetc ,
|
|
.Fn getc
|
|
and
|
|
.Fn getchar
|
|
functions
|
|
conform to
|
|
.St -ansiC .
|
|
The
|
|
.Fn getc_unlocked
|
|
and
|
|
.Fn getchar_unlocked
|
|
functions conform to
|
|
.St -p1003.1-96 .
|
|
.Sh BUGS
|
|
Since
|
|
.Dv EOF
|
|
is a valid integer value,
|
|
.Xr feof 3
|
|
and
|
|
.Xr ferror 3
|
|
must be used to check for failure after calling
|
|
.Fn getw .
|
|
The size and byte order of an
|
|
.Em int
|
|
varies from one machine to another, and
|
|
.Fn getw
|
|
is not recommended for portable applications.
|