getw.c

来自「C语言库函数的原型,有用的拿去」· C语言 代码 · 共 65 行

/***
*getw.c - read a binary word from a stream
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines _getw() - gets a binary integer from a stream
*
*******************************************************************************/

#include <cruntime.h>
#include <stdio.h>
#include <dbgint.h>
#include <file2.h>
#include <internal.h>
#include <mtdll.h>

/***
*int _getw(stream) - read an int from a stream
*
*Purpose:
*       get n bytes (n=sizeof(int)); OR them together in proper order; high
*       byte first. check for EOF between getc's.
*       this routine should be machine independent.
*
*Entry:
*       FILE *stream - stream to read integer from
*
*Exit:
*       returns the int read from the stream
*       returns EOF if fails (but this is a legit int value, so
*       should test feof() or ferror().
*
*Exceptions:
*
*******************************************************************************/

int __cdecl _getw (
        FILE *str
        )
{
    REG1 FILE *stream;
    REG2 int bytecount = sizeof(int);
    int word;
    char *byteptr = (char *)&word;
    int retval;

    _VALIDATE_RETURN((str != NULL), EINVAL, EOF);

    /* Init stream pointer */
    stream = str;

    _lock_str(stream);
    __try {
        while (bytecount--)
            *byteptr++ = (char)_getc_nolock(stream);
        retval = ((feof(stream) || ferror(stream)) ? EOF : word);
    }
    __finally {
        _unlock_str(stream);
    }

    return(retval);
}