<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <link rel="stylesheet" href="style.css" type="text/css"> <meta content="text/html; charset=iso-8859-1" http-equiv="Content-Type"> <link rel="Start" href="index.html"> <link rel="previous" href="MoreLabels.html"> <link rel="next" href="Nativeint.html"> <link rel="Up" href="index.html"> <link title="Index of types" rel=Appendix href="index_types.html"> <link title="Index of exceptions" rel=Appendix href="index_exceptions.html"> <link title="Index of values" rel=Appendix href="index_values.html"> <link title="Index of modules" rel=Appendix href="index_modules.html"> <link title="Index of module types" rel=Appendix href="index_module_types.html"> <link title="Arg" rel="Chapter" href="Arg.html"> <link title="Arith_status" rel="Chapter" href="Arith_status.html"> <link title="Array" rel="Chapter" href="Array.html"> <link title="ArrayLabels" rel="Chapter" href="ArrayLabels.html"> <link title="Big_int" rel="Chapter" href="Big_int.html"> <link title="Bigarray" rel="Chapter" href="Bigarray.html"> <link title="Buffer" rel="Chapter" href="Buffer.html"> <link title="Callback" rel="Chapter" href="Callback.html"> <link title="CamlinternalLazy" rel="Chapter" href="CamlinternalLazy.html"> <link title="CamlinternalMod" rel="Chapter" href="CamlinternalMod.html"> <link title="CamlinternalOO" rel="Chapter" href="CamlinternalOO.html"> <link title="Char" rel="Chapter" href="Char.html"> <link title="Complex" rel="Chapter" href="Complex.html"> <link title="Condition" rel="Chapter" href="Condition.html"> <link title="Digest" rel="Chapter" href="Digest.html"> <link title="Dynlink" rel="Chapter" href="Dynlink.html"> <link title="Event" rel="Chapter" href="Event.html"> <link title="Filename" rel="Chapter" href="Filename.html"> <link title="Format" rel="Chapter" href="Format.html"> <link title="Gc" rel="Chapter" href="Gc.html"> <link title="Genlex" rel="Chapter" href="Genlex.html"> <link title="Graphics" rel="Chapter" href="Graphics.html"> <link title="GraphicsX11" rel="Chapter" href="GraphicsX11.html"> <link title="Hashtbl" rel="Chapter" href="Hashtbl.html"> <link title="Int32" rel="Chapter" href="Int32.html"> <link title="Int64" rel="Chapter" href="Int64.html"> <link title="Lazy" rel="Chapter" href="Lazy.html"> <link title="Lexing" rel="Chapter" href="Lexing.html"> <link title="List" rel="Chapter" href="List.html"> <link title="ListLabels" rel="Chapter" href="ListLabels.html"> <link title="Map" rel="Chapter" href="Map.html"> <link title="Marshal" rel="Chapter" href="Marshal.html"> <link title="MoreLabels" rel="Chapter" href="MoreLabels.html"> <link title="Mutex" rel="Chapter" href="Mutex.html"> <link title="Nativeint" rel="Chapter" href="Nativeint.html"> <link title="Num" rel="Chapter" href="Num.html"> <link title="Obj" rel="Chapter" href="Obj.html"> <link title="Oo" rel="Chapter" href="Oo.html"> <link title="Parsing" rel="Chapter" href="Parsing.html"> <link title="Pervasives" rel="Chapter" href="Pervasives.html"> <link title="Printexc" rel="Chapter" href="Printexc.html"> <link title="Printf" rel="Chapter" href="Printf.html"> <link title="Queue" rel="Chapter" href="Queue.html"> <link title="Random" rel="Chapter" href="Random.html"> <link title="Ratio" rel="Chapter" href="Ratio.html"> <link title="Scanf" rel="Chapter" href="Scanf.html"> <link title="Set" rel="Chapter" href="Set.html"> <link title="Sort" rel="Chapter" href="Sort.html"> <link title="Stack" rel="Chapter" href="Stack.html"> <link title="StdLabels" rel="Chapter" href="StdLabels.html"> <link title="Str" rel="Chapter" href="Str.html"> <link title="Stream" rel="Chapter" href="Stream.html"> <link title="String" rel="Chapter" href="String.html"> <link title="StringLabels" rel="Chapter" href="StringLabels.html"> <link title="Sys" rel="Chapter" href="Sys.html"> <link title="Thread" rel="Chapter" href="Thread.html"> <link title="ThreadUnix" rel="Chapter" href="ThreadUnix.html"> <link title="Tk" rel="Chapter" href="Tk.html"> <link title="Unix" rel="Chapter" href="Unix.html"> <link title="UnixLabels" rel="Chapter" href="UnixLabels.html"> <link title="Weak" rel="Chapter" href="Weak.html"><title>Mutex</title> </head> <body> <div class="navbar"><a class="pre" href="MoreLabels.html" title="MoreLabels">Previous</a> <a class="up" href="index.html" title="Index">Up</a> <a class="post" href="Nativeint.html" title="Nativeint">Next</a> </div> <h1>Module <a href="type_Mutex.html">Mutex</a></h1> <pre><span class="keyword">module</span> Mutex: <code class="code"><span class="keyword">sig</span></code> <a href="Mutex.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info module top"> Locks for mutual exclusion. <p> Mutexes (mutual-exclusion locks) are used to implement critical sections and protect shared mutable data structures against concurrent accesses. The typical use is (if <code class="code">m</code> is the mutex associated with the data structure <code class="code"><span class="constructor">D</span></code>): <pre class="codepre"><code class="code"> <span class="constructor">Mutex</span>.lock m;<br> <span class="comment">(* Critical section that operates over D *)</span>;<br> <span class="constructor">Mutex</span>.unlock m<br> </code></pre><br> </div> <hr width="100%"> <pre><span id="TYPEt"><span class="keyword">type</span> <code class="type"></code>t</span> </pre> <div class="info "> The type of mutexes.<br> </div> <pre><span id="VALcreate"><span class="keyword">val</span> create</span> : <code class="type">unit -> <a href="Mutex.html#TYPEt">t</a></code></pre><div class="info "> Return a new mutex.<br> </div> <pre><span id="VALlock"><span class="keyword">val</span> lock</span> : <code class="type"><a href="Mutex.html#TYPEt">t</a> -> unit</code></pre><div class="info "> Lock the given mutex. Only one thread can have the mutex locked at any time. A thread that attempts to lock a mutex already locked by another thread will suspend until the other thread unlocks the mutex.<br> </div> <pre><span id="VALtry_lock"><span class="keyword">val</span> try_lock</span> : <code class="type"><a href="Mutex.html#TYPEt">t</a> -> bool</code></pre><div class="info "> Same as <a href="Mutex.html#VALlock"><code class="code"><span class="constructor">Mutex</span>.lock</code></a>, but does not suspend the calling thread if the mutex is already locked: just return <code class="code"><span class="keyword">false</span></code> immediately in that case. If the mutex is unlocked, lock it and return <code class="code"><span class="keyword">true</span></code>.<br> </div> <pre><span id="VALunlock"><span class="keyword">val</span> unlock</span> : <code class="type"><a href="Mutex.html#TYPEt">t</a> -> unit</code></pre><div class="info "> Unlock the given mutex. Other threads suspended trying to lock the mutex will restart.<br> </div> </body></html>