<!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="Lwt_mvar.html"> <link rel="next" href="Lwt_sequence.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 class attributes" rel=Appendix href="index_attributes.html"> <link title="Index of class methods" rel=Appendix href="index_methods.html"> <link title="Index of classes" rel=Appendix href="index_classes.html"> <link title="Index of class types" rel=Appendix href="index_class_types.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="Lwt_condition" rel="Chapter" href="Lwt_condition.html"> <link title="Lwt_list" rel="Chapter" href="Lwt_list.html"> <link title="Lwt" rel="Chapter" href="Lwt.html"> <link title="Lwt_mutex" rel="Chapter" href="Lwt_mutex.html"> <link title="Lwt_mvar" rel="Chapter" href="Lwt_mvar.html"> <link title="Lwt_pool" rel="Chapter" href="Lwt_pool.html"> <link title="Lwt_sequence" rel="Chapter" href="Lwt_sequence.html"> <link title="Lwt_stream" rel="Chapter" href="Lwt_stream.html"> <link title="Lwt_switch" rel="Chapter" href="Lwt_switch.html"> <link title="Lwt_util" rel="Chapter" href="Lwt_util.html"> <link title="Lwt_pqueue" rel="Chapter" href="Lwt_pqueue.html"> <link title="Lwt_lib" rel="Chapter" href="Lwt_lib.html"> <link title="Lwt_glib" rel="Chapter" href="Lwt_glib.html"> <link title="Lwt_preemptive" rel="Chapter" href="Lwt_preemptive.html"> <link title="Lwt_event" rel="Chapter" href="Lwt_event.html"> <link title="Lwt_signal" rel="Chapter" href="Lwt_signal.html"> <link title="Lwt_react" rel="Chapter" href="Lwt_react.html"> <link title="Lwt_ssl" rel="Chapter" href="Lwt_ssl.html"> <link title="Lwt_text" rel="Chapter" href="Lwt_text.html"> <link title="Lwt_term" rel="Chapter" href="Lwt_term.html"> <link title="Lwt_read_line" rel="Chapter" href="Lwt_read_line.html"> <link title="Lwt_top" rel="Chapter" href="Lwt_top.html"> <link title="Lwt_chan" rel="Chapter" href="Lwt_chan.html"> <link title="Lwt_daemon" rel="Chapter" href="Lwt_daemon.html"> <link title="Lwt_gc" rel="Chapter" href="Lwt_gc.html"> <link title="Lwt_io" rel="Chapter" href="Lwt_io.html"> <link title="Lwt_log" rel="Chapter" href="Lwt_log.html"> <link title="Lwt_main" rel="Chapter" href="Lwt_main.html"> <link title="Lwt_process" rel="Chapter" href="Lwt_process.html"> <link title="Lwt_throttle" rel="Chapter" href="Lwt_throttle.html"> <link title="Lwt_timeout" rel="Chapter" href="Lwt_timeout.html"> <link title="Lwt_unix" rel="Chapter" href="Lwt_unix.html"> <link title="Lwt_sys" rel="Chapter" href="Lwt_sys.html"> <link title="Lwt_engine" rel="Chapter" href="Lwt_engine.html"> <link title="Lwt_bytes" rel="Chapter" href="Lwt_bytes.html"> <link title="Pa_lwt" rel="Chapter" href="Pa_lwt.html"> <link title="Pa_lwt_log" rel="Chapter" href="Pa_lwt_log.html"><title>Lwt_pool</title> </head> <body> <div class="navbar"><a class="pre" href="Lwt_mvar.html" title="Lwt_mvar">Previous</a> <a class="up" href="index.html" title="Index">Up</a> <a class="post" href="Lwt_sequence.html" title="Lwt_sequence">Next</a> </div> <h1>Module <a href="type_Lwt_pool.html">Lwt_pool</a></h1> <pre><span class="keyword">module</span> Lwt_pool: <code class="code"><span class="keyword">sig</span></code> <a href="Lwt_pool.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info"> Creating pools (for example pools of connections to a database).<br> </div> <hr width="100%"> <br> Instead of creating a new connection each time you need one, keep a pool of opened connections and reuse opened connections that are free.<br> <pre><span id="TYPEt"><span class="keyword">type</span> <code class="type">'a</code> t</span> </pre> <div class="info"> Type of pools<br> </div> <pre><span id="VALcreate"><span class="keyword">val</span> create</span> : <code class="type">int -><br> ?check:('a -> (bool -> unit) -> unit) -><br> ?validate:('a -> bool <a href="Lwt.html#TYPEt">Lwt.t</a>) -> (unit -> 'a <a href="Lwt.html#TYPEt">Lwt.t</a>) -> 'a <a href="Lwt_pool.html#TYPEt">t</a></code></pre><div class="info"> <code class="code">create n ?check ?validate f</code> creates a new pool with at most <code class="code">n</code> members. <code class="code">f</code> is the function to use to create a new pool member. <p> An element of the pool is validated by the optional <code class="code">validate</code> function before its <a href="Lwt_pool.html#VALuse"><code class="code"><span class="constructor">Lwt_pool</span>.use</code></a>. Invalid elements are re-created. <p> The optional function <code class="code">check</code> is called after a <code class="code">use</code> of an element failed. It must call its argument excatly one with <code class="code"><span class="keyword">true</span></code> if the pool member is still valid and <code class="code"><span class="keyword">false</span></code> otherwise.<br> </div> <pre><span id="VALuse"><span class="keyword">val</span> use</span> : <code class="type">'a <a href="Lwt_pool.html#TYPEt">t</a> -> ('a -> 'b <a href="Lwt.html#TYPEt">Lwt.t</a>) -> 'b <a href="Lwt.html#TYPEt">Lwt.t</a></code></pre><div class="info"> <code class="code">use p f</code> takes one free member of the pool <code class="code">p</code> and gives it to the function <code class="code">f</code>.<br> </div> </body></html>