fleni64.c

C语言库函数的原型,有用的拿去

/***
*fleni64.c - find length of a file
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines _filelengthi64() - find the length of a file
*
*******************************************************************************/

#include <cruntime.h>
#include <stdio.h>
#include <errno.h>
#include <io.h>
#include <internal.h>
#include <msdos.h>
#include <mtdll.h>
#include <stddef.h>
#include <stdlib.h>

/***
*__int64 _filelengthi64(filedes) - find length of a file
*
*Purpose:
*       Returns the length in bytes of the specified file.
*
*Entry:
*       int filedes - handle referring to file to find length of
*
*Exit:
*       returns length of file in bytes
*       returns -1i64 if fails
*
*Exceptions:
*
*******************************************************************************/

__int64 __cdecl _filelengthi64 (
        int filedes
        )
{
        __int64 length;
        __int64 here;

        _CHECK_FH_CLEAR_OSSERR_RETURN( filedes, EBADF, -1i64 );
        _VALIDATE_CLEAR_OSSERR_RETURN((filedes >= 0 && (unsigned)filedes < (unsigned)_nhandle), EBADF, -1i64);
        _VALIDATE_CLEAR_OSSERR_RETURN((_osfile(filedes) & FOPEN), EBADF, -1i64);

        _lock_fh(filedes);
        __try {
            if ( _osfile(filedes) & FOPEN ) {
                                /* Seek to end (and back) to get the file length. */

                                if ( (here = _lseeki64_nolock( filedes, 0i64, SEEK_CUR )) == -1i64 )
                                        length = -1i64;     /* return error */
                                else {
                                        length = _lseeki64_nolock( filedes, 0i64, SEEK_END );
                                        if ( here != length )
                                                _lseeki64_nolock( filedes, here, SEEK_SET );
                                }
            }
            else {
                    errno = EBADF;
                    _doserrno = 0L;
                    length = -1i64;
                    _ASSERTE(("Invalid file descriptor. File possibly closed by a different thread",0));
            }
        }
        __finally {
                _unlock_fh(filedes);
        }

        return( length );
}