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<pre><a name="line-1"></a><span class='hs-comment'>{-# OPTIONS_GHC -XNoImplicitPrelude #-}</span>
<a name="line-2"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-3"></a><span class='hs-comment'>-- |</span>
<a name="line-4"></a><span class='hs-comment'>-- Module : Foreign.Marshal</span>
<a name="line-5"></a><span class='hs-comment'>-- Copyright : (c) The FFI task force 2003</span>
<a name="line-6"></a><span class='hs-comment'>-- License : BSD-style (see the file libraries/base/LICENSE)</span>
<a name="line-7"></a><span class='hs-comment'>-- </span>
<a name="line-8"></a><span class='hs-comment'>-- Maintainer : ffi@haskell.org</span>
<a name="line-9"></a><span class='hs-comment'>-- Stability : provisional</span>
<a name="line-10"></a><span class='hs-comment'>-- Portability : portable</span>
<a name="line-11"></a><span class='hs-comment'>--</span>
<a name="line-12"></a><span class='hs-comment'>-- Marshalling support</span>
<a name="line-13"></a><span class='hs-comment'>--</span>
<a name="line-14"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span>
<a name="line-17"></a> <span class='hs-layout'>(</span>
<a name="line-18"></a> <span class='hs-comment'>-- | The module "Foreign.Marshal" re-exports the other modules in the</span>
<a name="line-19"></a> <span class='hs-comment'>-- @Foreign.Marshal@ hierarchy:</span>
<a name="line-20"></a> <span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Alloc</span>
<a name="line-21"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Array</span>
<a name="line-22"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span>
<a name="line-23"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Pool</span>
<a name="line-24"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span>
<a name="line-25"></a> <span class='hs-comment'>-- | and provides one function:</span>
<a name="line-26"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>unsafeLocalState</span>
<a name="line-27"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-28"></a>
<a name="line-29"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Alloc</span>
<a name="line-30"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Array</span>
<a name="line-31"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span>
<a name="line-32"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Pool</span>
<a name="line-33"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Marshal</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span>
<a name="line-34"></a>
<a name="line-35"></a><span class='hs-cpp'>#ifdef __GLASGOW_HASKELL__</span>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>GHC</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span>
<a name="line-37"></a><span class='hs-cpp'>#else</span>
<a name="line-38"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span>
<a name="line-39"></a><span class='hs-cpp'>#endif</span>
<a name="line-40"></a>
<a name="line-41"></a><a name="unsafeLocalState"></a><span class='hs-comment'>{- |
<a name="line-42"></a>Sometimes an external entity is a pure function, except that it passes
<a name="line-43"></a>arguments and/or results via pointers. The function
<a name="line-44"></a>@unsafeLocalState@ permits the packaging of such entities as pure
<a name="line-45"></a>functions.
<a name="line-46"></a>
<a name="line-47"></a>The only IO operations allowed in the IO action passed to
<a name="line-48"></a>@unsafeLocalState@ are (a) local allocation (@alloca@, @allocaBytes@
<a name="line-49"></a>and derived operations such as @withArray@ and @withCString@), and (b)
<a name="line-50"></a>pointer operations (@Foreign.Storable@ and @Foreign.Ptr@) on the
<a name="line-51"></a>pointers to local storage, and (c) foreign functions whose only
<a name="line-52"></a>observable effect is to read and/or write the locally allocated
<a name="line-53"></a>memory. Passing an IO operation that does not obey these rules
<a name="line-54"></a>results in undefined behaviour.
<a name="line-55"></a>
<a name="line-56"></a>It is expected that this operation will be
<a name="line-57"></a>replaced in a future revision of Haskell.
<a name="line-58"></a>-}</span>
<a name="line-59"></a><span class='hs-definition'>unsafeLocalState</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-60"></a><span class='hs-definition'>unsafeLocalState</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span>
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