UnlockFile
The UnlockFile
function unlocks a region in an open file. Unlocking a region enables other
processes to access the region.
BOOL UnlockFile(
|
HANDLE hFile, |
// handle of file
to unlock |
|
DWORD dwFileOffsetLow, |
// low-order word
of lock region offset |
|
DWORD dwFileOffsetHigh, |
// high-order word
of lock region offset |
|
DWORD nNumberOfBytesToUnlockLow, |
// low-order word
of length to unlock |
|
DWORD
nNumberOfBytesToUnlockHigh |
// high-order word
of length to unlock |
|
); |
|
Parameters
hFile
Identifies a
file that contains a region locked with LockFile. The file handle must have
been created with either GENERIC_READ or GENERIC_WRITE access to the file.
dwFileOffsetLow
Specifies the
low-order word of the starting byte offset in the file where the locked region
begins.
dwFileOffsetHigh
Specifies the
high-order word of the starting byte offset in the file where the locked region
begins.
nNumberOfBytesToUnlockLow
Specifies the
low-order word of the length of the byte range to be unlocked.
nNumberOfBytesToUnlockHigh
Specifies the
high-order word of the length of the byte range to be unlocked.
Return Values
If the
function succeeds, the return value is nonzero.
If the
function fails, the return value is zero. To get extended error information,
call GetLastError.
Remarks
Unlocking a
region of a file releases a lock on the file. The region to unlock must
correspond exactly to an existing locked region. For example, two adjacent
regions of a file cannot be locked separately and then unlocked as a single
region that spans both locked regions.
A process
should not be terminated with a portion of a file locked and a file that has
locked regions should not be closed.
This function
works on a file allocation table (FAT) - based file system only if the operating system is running SHARE.EXE.
See Also