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<title>System/Timeout/Lifted.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP, UnicodeSyntax, NoImplicitPrelude, FlexibleContexts #-}</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-4"></a><span class='hs-comment'>-- |</span>
<a name="line-5"></a><span class='hs-comment'>-- Module : System.Timeout.Lifted</span>
<a name="line-6"></a><span class='hs-comment'>-- Copyright : (c) The University of Glasgow 2007</span>
<a name="line-7"></a><span class='hs-comment'>-- License : BSD-style (see the file libraries/base/LICENSE)</span>
<a name="line-8"></a><span class='hs-comment'>--</span>
<a name="line-9"></a><span class='hs-comment'>-- Maintainer : libraries@haskell.org</span>
<a name="line-10"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-11"></a><span class='hs-comment'>-- Portability : non-portable</span>
<a name="line-12"></a><span class='hs-comment'>--</span>
<a name="line-13"></a><span class='hs-comment'>-- Attach a timeout event to monadic computations</span>
<a name="line-14"></a><span class='hs-comment'>-- which are instances of 'MonadBaseControl'.</span>
<a name="line-15"></a><span class='hs-comment'>--</span>
<a name="line-16"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-17"></a>
<a name="line-18"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Timeout</span><span class='hs-varop'>.</span><span class='hs-conid'>Lifted</span> <span class='hs-layout'>(</span> <span class='hs-varid'>timeout</span> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-19"></a>
<a name="line-20"></a><span class='hs-comment'>-- from base:</span>
<a name="line-21"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Int</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Int</span> <span class='hs-layout'>)</span>
<a name="line-22"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Maybe</span><span class='hs-layout'>(</span><span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>maybe</span> <span class='hs-layout'>)</span>
<a name="line-23"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span> <span class='hs-layout'>(</span><span class='hs-varop'>>>=</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>return</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftM</span> <span class='hs-layout'>)</span>
<a name="line-24"></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-layout'>(</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>)</span>
<a name="line-25"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Timeout</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>T</span> <span class='hs-layout'>(</span> <span class='hs-varid'>timeout</span> <span class='hs-layout'>)</span>
<a name="line-26"></a>
<a name="line-27"></a><span class='hs-comment'>-- from base-unicode-symbols:</span>
<a name="line-28"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Function</span><span class='hs-varop'>.</span><span class='hs-conid'>Unicode</span> <span class='hs-layout'>(</span> <span class='hs-layout'>(</span><span class='hs-sel'>∘</span><span class='hs-layout'>)</span> <span class='hs-layout'>)</span>
<a name="line-29"></a>
<a name="line-30"></a><span class='hs-comment'>-- from monad-control:</span>
<a name="line-31"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Trans</span><span class='hs-varop'>.</span><span class='hs-conid'>Control</span> <span class='hs-layout'>(</span> <span class='hs-conid'>MonadBaseControl</span><span class='hs-layout'>,</span> <span class='hs-varid'>restoreM</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftBaseWith</span> <span class='hs-layout'>)</span>
<a name="line-32"></a>
<a name="line-33"></a><span class='hs-cpp'>#include "inlinable.h"</span>
<a name="line-34"></a>
<a name="line-35"></a><a name="timeout"></a><span class='hs-comment'>-- | Generalized version of 'T.timeout'.</span>
<a name="line-36"></a><span class='hs-comment'>--</span>
<a name="line-37"></a><span class='hs-comment'>-- Note that when the given computation times out any side effects of @m@ are</span>
<a name="line-38"></a><span class='hs-comment'>-- discarded. When the computation completes within the given time the</span>
<a name="line-39"></a><span class='hs-comment'>-- side-effects are restored on return.</span>
<a name="line-40"></a><span class='hs-definition'>timeout</span> <span class='hs-sel'>∷</span> <span class='hs-conid'>MonadBaseControl</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>m</span> <span class='hs-sel'>⇒</span> <span class='hs-conid'>Int</span> <span class='hs-sel'>→</span> <span class='hs-varid'>m</span> <span class='hs-varid'>α</span> <span class='hs-sel'>→</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>α</span><span class='hs-layout'>)</span>
<a name="line-41"></a><span class='hs-definition'>timeout</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftBaseWith</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>runInIO</span> <span class='hs-sel'>→</span> <span class='hs-conid'>T</span><span class='hs-varop'>.</span><span class='hs-varid'>timeout</span> <span class='hs-varid'>t</span> <span class='hs-layout'>(</span><span class='hs-varid'>runInIO</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>=</span>
<a name="line-42"></a> <span class='hs-varid'>maybe</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-conid'>Just</span> <span class='hs-sel'>∘</span> <span class='hs-varid'>restoreM</span><span class='hs-layout'>)</span>
<a name="line-43"></a><span class='hs-comment'>{-# INLINABLE timeout #-}</span>
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