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

108 lines
2.9 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
<<getc>>---read a character (macro)
INDEX
getc
INDEX
_getc_r
SYNOPSIS
#include <stdio.h>
int getc(FILE *<[fp]>);
#include <stdio.h>
int _getc_r(struct _reent *<[ptr]>, FILE *<[fp]>);
DESCRIPTION
<<getc>> is a macro, defined in <<stdio.h>>. You can use <<getc>>
to get the next single character from the file or stream
identified by <[fp]>. As a side effect, <<getc>> advances the file's
current position indicator.
For a subroutine version of this macro, see <<fgetc>>.
The <<_getc_r>> function is simply the reentrant version of <<getc>>
which passes an additional reentrancy 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, <<getc>> returns <<EOF>>.
You can distinguish the two situations that cause an <<EOF>> result by
using the <<ferror>> and <<feof>> functions.
PORTABILITY
ANSI C requires <<getc>>; it suggests, but does not require, that
<<getc>> be implemented as a macro. The standard explicitly permits
macro implementations of <<getc>> to use the argument more than once;
therefore, in a portable program, you should not use an expression
with side effects as the <<getc>> argument.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
#include <_ansi.h>
#include <stdio.h>
#include "local.h"
/*
* A subroutine version of the macro getc.
*/
#undef getc
int
_DEFUN(_getc_r, (ptr, fp),
struct _reent *ptr,
register 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
_DEFUN(getc, (fp),
register FILE *fp)
{
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;
}
#endif /* !_REENT_ONLY */