drivfree.cpp File Reference

#include <corecrt_internal.h>
#include <direct.h>

Include dependency graph for drivfree.cpp:

Go to the source code of this file.

Functions
unsigned __cdecl	_getdiskfree (unsigned const drive_number, _diskfree_t *const result)

Function Documentation

_getdiskfree()

unsigned __cdecl _getdiskfree	(	unsigned const	drive_number,
		_diskfree_t *const	result
	)

Definition at line 19 of file drivfree.cpp.

{
    _VALIDATE_RETURN(result != nullptr,  EINVAL, ERROR_INVALID_PARAMETER);
    _VALIDATE_RETURN(drive_number <= 26, EINVAL, ERROR_INVALID_PARAMETER);
 
    *result = _diskfree_t();
 
    wchar_t drive_name_buffer[4] = { '_', ':', '\\', '\0' };
 
    wchar_t const* const drive_name = drive_number == 0
        ? nullptr
        : drive_name_buffer;
 
    if (drive_number != 0)
    {
        drive_name_buffer[0] = static_cast<wchar_t>(drive_number) + static_cast<wchar_t>(L'A' - 1);
    }
 
    static_assert(sizeof(result->sectors_per_cluster) == sizeof(DWORD), "Unexpected sizeof long");
 
    if (!GetDiskFreeSpaceW(drive_name,
        reinterpret_cast<LPDWORD>(&result->sectors_per_cluster),
        reinterpret_cast<LPDWORD>(&result->bytes_per_sector),
        reinterpret_cast<LPDWORD>(&result->avail_clusters),
        reinterpret_cast<LPDWORD>(&result->total_clusters)))
    {
        int const os_error = GetLastError();
        errno = __acrt_errno_from_os_error(os_error);
 
        return os_error;
    }
 
    return 0;
}