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/*-
* Copyright (c) 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __wt_bytelock --
* Lock/unlock a byte in a file.
*/
int
__wt_bytelock(WT_FH *fhp, wt_off_t byte, bool lock)
{
WT_DECL_RET;
/*
* WiredTiger requires this function be able to acquire locks past
* the end of file.
*
* Note we're using fcntl(2) locking: all fcntl locks associated with a
* file for a given process are removed when any file descriptor for the
* file is closed by the process, even if a lock was never requested for
* that file descriptor.
*
* http://msdn.microsoft.com/
* en-us/library/windows/desktop/aa365202%28v=vs.85%29.aspx
*
* You can lock bytes that are beyond the end of the current file.
* This is useful to coordinate adding records to the end of a file.
*/
if (lock) {
ret = LockFile(fhp->filehandle, UINT32_MAX & byte,
UINT32_MAX & (byte >> 32), 1, 0);
} else {
ret = UnlockFile(fhp->filehandle, UINT32_MAX & byte,
UINT32_MAX & (byte >> 32), 1, 0);
}
if (ret == FALSE)
WT_RET_MSG(NULL, __wt_errno(), "%s: LockFile", fhp->name);
return (0);
}
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