<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <title>Apache Portable Runtime: Optional Functions</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <link href="search/search.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="search/search.js"></script> <link href="doxygen.css" rel="stylesheet" type="text/css"/> </head> <body onload='searchBox.OnSelectItem(0);'> <!-- Generated by Doxygen 1.7.3 --> <script type="text/javascript"><!-- var searchBox = new SearchBox("searchBox", "search",false,'Search'); --></script> <div id="top"> <div id="titlearea"> <table cellspacing="0" cellpadding="0"> <tbody> <tr style="height: 56px;"> <td style="padding-left: 0.5em;"> <div id="projectname">Apache Portable Runtime</div> </td> </tr> </tbody> </table> </div> <div 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src="search/close.png" alt=""/></a> </span> </div> </li> </ul> </div> </div> <div class="header"> <div class="summary"> <a href="#define-members">Defines</a> | <a href="#typedef-members">Typedefs</a> | <a href="#func-members">Functions</a> </div> <div class="headertitle"> <h1>Optional Functions</h1> </div> <div class="ingroups"><a class="el" href="group___a_p_r___util.html">APR Utility Functions</a></div></div> <div class="contents"> <table class="memberdecls"> <tr><td colspan="2"><h2><a name="define-members"></a> Defines</h2></td></tr> <tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group___a_p_r___util___opt.html#ga987fcf75505450f1b4ff9d7b3a7ff5d3">APR_OPTIONAL_FN_TYPE</a>(name)   apr_OFN_##name##_t</td></tr> <tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group___a_p_r___util___opt.html#gaf3ff372e28978d4ce0be7517ca2fddbd">APR_DECLARE_OPTIONAL_FN</a>(ret, name, args)   typedef ret (APR_OPTIONAL_FN_TYPE(name)) args</td></tr> <tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group___a_p_r___util___opt.html#gab611deabd6e78b5f666071e8cbdcc736">APR_REGISTER_OPTIONAL_FN</a>(name)</td></tr> <tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group___a_p_r___util___opt.html#ga35f2df25ca06248d2fdd3e7463446418">APR_RETRIEVE_OPTIONAL_FN</a>(name)   (APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)</td></tr> <tr><td colspan="2"><h2><a name="typedef-members"></a> Typedefs</h2></td></tr> <tr><td class="memItemLeft" align="right" valign="top">typedef void( </td><td class="memItemRight" valign="bottom"><a class="el" href="group___a_p_r___util___opt.html#ga35e08c2dbf593e3dc5a2cb0fdc8cd637">apr_opt_fn_t</a> )(void)</td></tr> <tr><td colspan="2"><h2><a name="func-members"></a> Functions</h2></td></tr> <tr><td class="memItemLeft" align="right" valign="top"><a class="anchor" id="gaa9c7d3cc32128521274543c384e9698d"></a><!-- doxytag: member="APR_Util_Opt::apr_dynamic_fn_register" ref="gaa9c7d3cc32128521274543c384e9698d" args="(const char *szName, apr_opt_fn_t *pfn)" --> void </td><td class="memItemRight" valign="bottom"><b>apr_dynamic_fn_register</b> (const char *szName, <a class="el" href="group___a_p_r___util___opt.html#ga35e08c2dbf593e3dc5a2cb0fdc8cd637">apr_opt_fn_t</a> *pfn)</td></tr> <tr><td class="memItemLeft" align="right" valign="top"><a class="anchor" id="ga1ecfa6a6ced7332d03b5867735a5e49d"></a><!-- doxytag: member="APR_Util_Opt::apr_dynamic_fn_retrieve" ref="ga1ecfa6a6ced7332d03b5867735a5e49d" args="(const char *szName)" --> <a class="el" href="group___a_p_r___util___opt.html#ga35e08c2dbf593e3dc5a2cb0fdc8cd637">apr_opt_fn_t</a> * </td><td class="memItemRight" valign="bottom"><b>apr_dynamic_fn_retrieve</b> (const char *szName)</td></tr> </table> <hr/><a name="_details"></a><h2>Detailed Description</h2> <p>Typesafe registration and retrieval of functions that may not be present (i.e. functions exported by optional modules) </p> <hr/><h2>Define Documentation</h2> <a class="anchor" id="gaf3ff372e28978d4ce0be7517ca2fddbd"></a><!-- doxytag: member="apr_optional.h::APR_DECLARE_OPTIONAL_FN" ref="gaf3ff372e28978d4ce0be7517ca2fddbd" args="(ret, name, args)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define APR_DECLARE_OPTIONAL_FN</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">ret, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"> </td> <td class="paramname">name, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"> </td> <td class="paramname">args </td> </tr> <tr> <td></td> <td>)</td> <td></td><td>   typedef ret (APR_OPTIONAL_FN_TYPE(name)) args</td> </tr> </table> </div> <div class="memdoc"> <p>Declare an optional function. </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">ret</td><td>The return type of the function </td></tr> <tr><td class="paramname">name</td><td>The name of the function </td></tr> <tr><td class="paramname">args</td><td>The function arguments (including brackets) </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="ga987fcf75505450f1b4ff9d7b3a7ff5d3"></a><!-- doxytag: member="apr_optional.h::APR_OPTIONAL_FN_TYPE" ref="ga987fcf75505450f1b4ff9d7b3a7ff5d3" args="(name)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define APR_OPTIONAL_FN_TYPE</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">name</td><td>)</td> <td>   apr_OFN_##name##_t</td> </tr> </table> </div> <div class="memdoc"> <p>The type of an optional function. </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">name</td><td>The name of the function </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="gab611deabd6e78b5f666071e8cbdcc736"></a><!-- doxytag: member="apr_optional.h::APR_REGISTER_OPTIONAL_FN" ref="gab611deabd6e78b5f666071e8cbdcc736" args="(name)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define APR_REGISTER_OPTIONAL_FN</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">name</td><td>)</td> <td></td> </tr> </table> </div> <div class="memdoc"> <b>Value:</b><div class="fragment"><pre class="fragment"><span class="keywordflow">do</span> { \ <a class="code" href="group___a_p_r___util___opt.html#ga987fcf75505450f1b4ff9d7b3a7ff5d3">APR_OPTIONAL_FN_TYPE</a>(name) *apu__opt = name; \ apr_dynamic_fn_register(#name,(<a class="code" href="group___a_p_r___util___opt.html#ga35e08c2dbf593e3dc5a2cb0fdc8cd637">apr_opt_fn_t</a> *)apu__opt); \ } <span class="keywordflow">while</span> (0) </pre></div><p>Register an optional function. This can be later retrieved, type-safely, by name. Like all global functions, the name must be unique. Note that, confusingly but correctly, the function itself can be static! </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">name</td><td>The name of the function </td></tr> </table> </dd> </dl> </div> </div> <a class="anchor" id="ga35f2df25ca06248d2fdd3e7463446418"></a><!-- doxytag: member="apr_optional.h::APR_RETRIEVE_OPTIONAL_FN" ref="ga35f2df25ca06248d2fdd3e7463446418" args="(name)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define APR_RETRIEVE_OPTIONAL_FN</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">name</td><td>)</td> <td>   (APR_OPTIONAL_FN_TYPE(name) *)apr_dynamic_fn_retrieve(#name)</td> </tr> </table> </div> <div class="memdoc"> <p>Retrieve an optional function. Returns NULL if the function is not present. </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">name</td><td>The name of the function </td></tr> </table> </dd> </dl> </div> </div> <hr/><h2>Typedef Documentation</h2> <a class="anchor" id="ga35e08c2dbf593e3dc5a2cb0fdc8cd637"></a><!-- doxytag: member="apr_optional.h::apr_opt_fn_t" ref="ga35e08c2dbf593e3dc5a2cb0fdc8cd637" args=")(void)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">typedef void( <a class="el" href="group___a_p_r___util___opt.html#ga35e08c2dbf593e3dc5a2cb0fdc8cd637">apr_opt_fn_t</a>)(void)</td> </tr> </table> </div> <div class="memdoc"> <p>XXX: This doesn't belong here, then! Private function! 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