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

83 lines
2.4 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
<<clearerr>>, <<clearerr_unlocked>>---clear file or stream error indicator
INDEX
clearerr
INDEX
clearerr_unlocked
SYNOPSIS
#include <stdio.h>
void clearerr(FILE *<[fp]>);
#define _BSD_SOURCE
#include <stdio.h>
void clearerr_unlocked(FILE *<[fp]>);
DESCRIPTION
The <<stdio>> functions maintain an error indicator with each file
pointer <[fp]>, to record whether any read or write errors have
occurred on the associated file or stream. Similarly, it maintains an
end-of-file indicator to record whether there is no more data in the
file.
Use <<clearerr>> to reset both of these indicators.
See <<ferror>> and <<feof>> to query the two indicators.
<<clearerr_unlocked>> is a non-thread-safe version of <<clearerr>>.
<<clearerr_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
<<clearerr_unlocked>> is equivalent to <<clearerr>>.
RETURNS
<<clearerr>> does not return a result.
PORTABILITY
ANSI C requires <<clearerr>>.
<<clearerr_unlocked>> is a BSD extension also provided by GNU libc.
No supporting OS subroutines are required.
*/
#include <_ansi.h>
#include <stdio.h>
#include "local.h"
/* A subroutine version of the macro clearerr. */
#undef clearerr
_VOID
_DEFUN(clearerr, (fp),
FILE * fp)
{
CHECK_INIT(_REENT, fp);
_newlib_flockfile_start (fp);
__sclearerr (fp);
_newlib_flockfile_end (fp);
}