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/* -----------------------------------------------------------------------------
*
* (c) The GHC Team, 2007-2009
*
* File locking support as required by Haskell
*
* Do not #include this file directly: #include "Rts.h" instead.
*
* To understand the structure of the RTS headers, see the wiki:
* https://gitlab.haskell.org/ghc/ghc/wikis/commentary/source-tree/includes
*
* ---------------------------------------------------------------------------*/
/* Note [RTS File locking]
* ~~~~~~~~~~~~~~~~~~~~~~~
*
* The Haskell report dictates certain file locking behaviour.
* This is specified in the Haskell98 report under: 21.2.3 File locking
*
* GHC does not rely on the platform it's on to implement this.
* Instead we keep track of locked files in a data structure in
* the RTS. This file provides the interface to this data structure.
*
* In the base libraries we then use this interface to "lock" files.
* This means it's very much still possible for users outside of the
* rts/base library to open the files in question even if they are
* locked.
* */
#pragma once
#include "Stg.h"
/* No valid FD would be negative, so use a word instead of int so the value
is compatible with a Windows handle. */
int lockFile(StgWord64 id, StgWord64 dev, StgWord64 ino, int for_writing);
int unlockFile(StgWord64 id);
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