newlib-cygwin/newlib/libc/stdio/fgetc.c

120 lines
3.3 KiB
C

/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
FUNCTION
<<fgetc>>, <<fgetc_unlocked>>---get a character from a file or stream
INDEX
fgetc
INDEX
fgetc_unlocked
INDEX
_fgetc_r
INDEX
_fgetc_unlocked_r
SYNOPSIS
#include <stdio.h>
int fgetc(FILE *<[fp]>);
#define _BSD_SOURCE
#include <stdio.h>
int fgetc_unlocked(FILE *<[fp]>);
#include <stdio.h>
int _fgetc_r(struct _reent *<[ptr]>, FILE *<[fp]>);
#define _BSD_SOURCE
#include <stdio.h>
int _fgetc_unlocked_r(struct _reent *<[ptr]>, FILE *<[fp]>);
DESCRIPTION
Use <<fgetc>> to get the next single character from the file or stream
identified by <[fp]>. As a side effect, <<fgetc>> advances the file's
current position indicator.
For a macro version of this function, see <<getc>>.
<<fgetc_unlocked>> is a non-thread-safe version of <<fgetc>>.
<<fgetc_unlocked>> may only safely be used within a scope
protected by flockfile() (or ftrylockfile()) and funlockfile(). This
function may safely be used in a multi-threaded program if and only
if they are called while the invoking thread owns the (FILE *)
object, as is the case after a successful call to the flockfile() or
ftrylockfile() functions. If threads are disabled, then
<<fgetc_unlocked>> is equivalent to <<fgetc>>.
The functions <<_fgetc_r>> and <<_fgetc_unlocked_r>> are simply reentrant
versions that are passed the additional reentrant structure pointer
argument: <[ptr]>.
RETURNS
The next character (read as an <<unsigned char>>, and cast to
<<int>>), unless there is no more data, or the host system reports a
read error; in either of these situations, <<fgetc>> returns <<EOF>>.
You can distinguish the two situations that cause an <<EOF>> result by
using the <<ferror>> and <<feof>> functions.
PORTABILITY
ANSI C requires <<fgetc>>.
<<fgetc_unlocked>> is a BSD extension also provided by GNU libc.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/
#include <_ansi.h>
#include <stdio.h>
#include "local.h"
int
_fgetc_r (struct _reent * ptr,
FILE * fp)
{
int result;
CHECK_INIT(ptr, fp);
_newlib_flockfile_start (fp);
result = __sgetc_r (ptr, fp);
_newlib_flockfile_end (fp);
return result;
}
#ifndef _REENT_ONLY
int
fgetc (FILE * fp)
{
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
int result;
struct _reent *reent = _REENT;
CHECK_INIT(reent, fp);
_newlib_flockfile_start (fp);
result = __sgetc_r (reent, fp);
_newlib_flockfile_end (fp);
return result;
#else
return _fgetc_r (_REENT, fp);
#endif
}
#endif /* !_REENT_ONLY */