1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3<html><head> 4<title>CURLOPT_OPENSOCKETFUNCTION man page</title> 5<meta name="generator" content="roffit"> 6<STYLE type="text/css"> 7P.level0 { 8 padding-left: 2em; 9} 10 11P.level1 { 12 padding-left: 4em; 13} 14 15P.level2 { 16 padding-left: 6em; 17} 18 19span.emphasis { 20 font-style: italic; 21} 22 23span.bold { 24 font-weight: bold; 25} 26 27span.manpage { 28 font-weight: bold; 29} 30 31h2.nroffsh { 32 background-color: #e0e0e0; 33} 34 35span.nroffip { 36 font-weight: bold; 37 font-size: 120%; 38 font-family: monospace; 39} 40 41p.roffit { 42 text-align: center; 43 font-size: 80%; 44} 45</STYLE> 46</head><body> 47 48<p class="level0"><a name="NAME"></a><h2 class="nroffsh">NAME</h2> 49<p class="level0">CURLOPT_OPENSOCKETFUNCTION - set callback for opening sockets <a name="SYNOPSIS"></a><h2 class="nroffsh">SYNOPSIS</h2> 50<p class="level0"><pre> 51<p class="level0">#include <curl/curl.h> 52 <p class="level0">typedef enum { 53 CURLSOCKTYPE_IPCXN, /* socket created for a specific IP connection */ 54 CURLSOCKTYPE_ACCEPT, /* socket created by accept() call */ 55 CURLSOCKTYPE_LAST /* never use */ 56 } curlsocktype; 57 <p class="level0">struct curl_sockaddr { 58 int family; 59 int socktype; 60 int protocol; 61 unsigned int addrlen; 62 struct sockaddr addr; 63 }; 64 <p class="level0">curl_socket_t opensocket_callback(void *clientp, 65 curlsocktype purpose, 66 struct curl_sockaddr *address); 67 <p class="level0">CURLcode curl_easy_setopt(CURL *handle, CURLOPT_OPENSOCKETFUNCTION, opensocket_callback); 68 </pre> 69<a name="DESCRIPTION"></a><h2 class="nroffsh">DESCRIPTION</h2> 70<p class="level0">Pass a pointer to your callback function, which should match the prototype shown above. 71<p class="level0">This callback function gets called by libcurl instead of the <span Class="emphasis">socket(2)</span> call. The callback's <span Class="emphasis">purpose</span> argument identifies the exact purpose for this particular socket: <span Class="emphasis">CURLSOCKTYPE_IPCXN</span> is for IP based connections and <span Class="emphasis">CURLSOCKTYPE_ACCEPT</span> is for sockets created after accept() - such as when doing active FTP. Future versions of libcurl may support more purposes. 72<p class="level0">The <span Class="emphasis">clientp</span> pointer contains whatever user-defined value set using the <a Class="emphasis" href="/CURLOPT_OPENSOCKETDATA.html">CURLOPT_OPENSOCKETDATA</a> function. 73<p class="level0">The callback gets the resolved peer address as the <span Class="emphasis">address</span> argument and is allowed to modify the address or refuse to connect completely. The callback function should return the newly created socket or <span Class="emphasis">CURL_SOCKET_BAD</span> in case no connection could be established or another error was detected. Any additional <span Class="emphasis">setsockopt(2)</span> calls can of course be done on the socket at the user's discretion. A <span Class="emphasis">CURL_SOCKET_BAD</span> return value from the callback function will signal an unrecoverable error to libcurl and it will return <span Class="emphasis">CURLE_COULDNT_CONNECT</span> from the function that triggered this callback. This return code can be used for IP address blacklisting. 74<p class="level0">If you want to pass in a socket with an already established connection, pass the socket back with this callback and then use <a Class="emphasis" href="/CURLOPT_SOCKOPTFUNCTION.html">CURLOPT_SOCKOPTFUNCTION</a> to signal that it already is connected. <a name="DEFAULT"></a><h2 class="nroffsh">DEFAULT</h2> 75<p class="level0">The default behavior is the equivalent of this: <pre> 76<p class="level0"> return socket(addr->family, addr->socktype, addr->protocol); 77 </pre> 78 79<p class="level0"><a name="PROTOCOLS"></a><h2 class="nroffsh">PROTOCOLS</h2> 80<p class="level0">All <a name="EXAMPLE"></a><h2 class="nroffsh">EXAMPLE</h2> 81<p class="level0"><a name="AVAILABILITY"></a><h2 class="nroffsh">AVAILABILITY</h2> 82<p class="level0">Added in 7.17.1. <a name="RETURN"></a><h2 class="nroffsh">RETURN VALUE</h2> 83<p class="level0">Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. <a name="SEE"></a><h2 class="nroffsh">SEE ALSO</h2> 84<p class="level0"><a Class="manpage" href="/CURLOPT_OPENSOCKETDATA.html">CURLOPT_OPENSOCKETDATA</a> <a Class="manpage" href="/CURLOPT_SOCKOPTFUNCTION.html">CURLOPT_SOCKOPTFUNCTION</a> <span Class="manpage"> </span> <a Class="manpage" href="/CURLOPT_CLOSESOCKETFUNCTION.html">CURLOPT_CLOSESOCKETFUNCTION</a> <span Class="manpage"> </span> <p class="roffit"> 85 This HTML page was made with <a href="http://daniel.haxx.se/projects/roffit/">roffit</a>. 86</body></html> 87