drivfree.c

C语言库函数的原型,有用的拿去

/***
*drivfree.c - Get the size of a disk
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       This file has _getdiskfree()
*
*******************************************************************************/

#include <cruntime.h>
#include <direct.h>
#include <oscalls.h>
#include <internal.h>

/***
*int _getdiskfree(drivenum, diskfree)  - get size of a specified disk
*
*Purpose:
*       Gets the size of the current or specified disk drive
*
*Entry:
*       int drivenum - 0 for current drive, or drive 1-26
*
*Exit:
*       returns 0 if succeeds
*       returns system error code on error.
*
*Exceptions:
*
*******************************************************************************/

#ifndef _WIN32
#error ERROR - ONLY WIN32 TARGET SUPPORTED!
#endif  /* _WIN32 */

unsigned __cdecl _getdiskfree (
    unsigned uDrive,
    struct _diskfree_t * pdf
)
{
    char   Root[4];
    char * pRoot;

    _VALIDATE_RETURN((pdf != NULL), EINVAL, ERROR_INVALID_PARAMETER);
    _VALIDATE_RETURN(( uDrive <= 26 ), EINVAL, ERROR_INVALID_PARAMETER);
    memset( pdf, 0, sizeof( struct _diskfree_t ) );

    if ( uDrive == 0 ) {
        pRoot = NULL;
    }
    else {
        pRoot = &Root[0];
        Root[0] = (char)uDrive + (char)('A' - 1);
        Root[1] = ':';
        Root[2] = '\\';
        Root[3] = '\0';
    }


    if ( !GetDiskFreeSpace( pRoot,
        (LPDWORD)&(pdf->sectors_per_cluster),
        (LPDWORD)&(pdf->bytes_per_sector),
        (LPDWORD)&(pdf->avail_clusters),
        (LPDWORD)&(pdf->total_clusters)) )
    {
        int err = GetLastError();
        errno = _get_errno_from_oserr(err);

        return ( err );
    }

    return ( 0 );
}