summaryrefslogtreecommitdiffstats
path: root/www/c3ref/progress_handler.html
diff options
context:
space:
mode:
Diffstat (limited to 'www/c3ref/progress_handler.html')
-rw-r--r--www/c3ref/progress_handler.html165
1 files changed, 165 insertions, 0 deletions
diff --git a/www/c3ref/progress_handler.html b/www/c3ref/progress_handler.html
new file mode 100644
index 0000000..4c0233a
--- /dev/null
+++ b/www/c3ref/progress_handler.html
@@ -0,0 +1,165 @@
+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<link href="../sqlite.css" rel="stylesheet">
+<title>Query Progress Callbacks</title>
+<!-- path=../ -->
+</head>
+<body>
+<div class=nosearch>
+<a href="../index.html">
+<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0">
+</a>
+<div><!-- IE hack to prevent disappearing logo --></div>
+<div class="tagline desktoponly">
+Small. Fast. Reliable.<br>Choose any three.
+</div>
+<div class="menu mainmenu">
+<ul>
+<li><a href="../index.html">Home</a>
+<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
+<li class='wideonly'><a href='../about.html'>About</a>
+<li class='desktoponly'><a href="../docs.html">Documentation</a>
+<li class='desktoponly'><a href="../download.html">Download</a>
+<li class='wideonly'><a href='../copyright.html'>License</a>
+<li class='desktoponly'><a href="../support.html">Support</a>
+<li class='desktoponly'><a href="../prosupport.html">Purchase</a>
+<li class='search' id='search_menubutton'>
+<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
+</ul>
+</div>
+<div class="menu submenu" id="submenu">
+<ul>
+<li><a href='../about.html'>About</a>
+<li><a href='../docs.html'>Documentation</a>
+<li><a href='../download.html'>Download</a>
+<li><a href='../support.html'>Support</a>
+<li><a href='../prosupport.html'>Purchase</a>
+</ul>
+</div>
+<div class="searchmenu" id="searchmenu">
+<form method="GET" action="../search">
+<select name="s" id="searchtype">
+<option value="d">Search Documentation</option>
+<option value="c">Search Changelog</option>
+</select>
+<input type="text" name="q" id="searchbox" value="">
+<input type="submit" value="Go">
+</form>
+</div>
+</div>
+<script>
+function toggle_div(nm) {
+var w = document.getElementById(nm);
+if( w.style.display=="block" ){
+w.style.display = "none";
+}else{
+w.style.display = "block";
+}
+}
+function toggle_search() {
+var w = document.getElementById("searchmenu");
+if( w.style.display=="block" ){
+w.style.display = "none";
+} else {
+w.style.display = "block";
+setTimeout(function(){
+document.getElementById("searchbox").focus()
+}, 30);
+}
+}
+function div_off(nm){document.getElementById(nm).style.display="none";}
+window.onbeforeunload = function(e){div_off("submenu");}
+/* Disable the Search feature if we are not operating from CGI, since */
+/* Search is accomplished using CGI and will not work without it. */
+if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
+document.getElementById("search_menubutton").style.display = "none";
+}
+/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
+function hideorshow(btn,obj){
+var x = document.getElementById(obj);
+var b = document.getElementById(btn);
+if( x.style.display!='none' ){
+x.style.display = 'none';
+b.innerHTML='show';
+}else{
+x.style.display = '';
+b.innerHTML='hide';
+}
+return false;
+}
+var antiRobot = 0;
+function antiRobotGo(){
+if( antiRobot!=3 ) return;
+antiRobot = 7;
+var j = document.getElementById("mtimelink");
+if(j && j.hasAttribute("data-href")) j.href=j.getAttribute("data-href");
+}
+function antiRobotDefense(){
+document.body.onmousedown=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousedown=null;
+}
+document.body.onmousemove=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousemove=null;
+}
+setTimeout(function(){
+antiRobot |= 1;
+antiRobotGo();
+}, 100)
+antiRobotGo();
+}
+antiRobotDefense();
+</script>
+<!-- keywords: sqlite3_progress_handler -->
+<div class=nosearch>
+<a href="../c3ref/intro.html"><h2>SQLite C Interface</h2></a>
+<h2>Query Progress Callbacks</h2>
+</div>
+<blockquote><pre>
+void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+</pre></blockquote>
+<p>
+The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+function X to be invoked periodically during long running calls to
+<a href="../c3ref/step.html">sqlite3_step()</a> and <a href="../c3ref/prepare.html">sqlite3_prepare()</a> and similar for
+database connection D. An example use for this
+interface is to keep a GUI updated during a large query.</p>
+
+<p>The parameter P is passed through as the only parameter to the
+callback function X. The parameter N is the approximate number of
+<a href="../opcode.html">virtual machine instructions</a> that are evaluated between successive
+invocations of the callback X. If N is less than one then the progress
+handler is disabled.</p>
+
+<p>Only a single progress handler may be defined at one time per
+<a href="../c3ref/sqlite3.html">database connection</a>; setting a new progress handler cancels the
+old one. Setting parameter X to NULL disables the progress handler.
+The progress handler is also disabled by setting N to a value less
+than 1.</p>
+
+<p>If the progress callback returns non-zero, the operation is
+interrupted. This feature can be used to implement a
+"Cancel" button on a GUI progress dialog box.</p>
+
+<p>The progress handler callback must not do anything that will modify
+the database connection that invoked the progress handler.
+Note that <a href="../c3ref/prepare.html">sqlite3_prepare_v2()</a> and <a href="../c3ref/step.html">sqlite3_step()</a> both modify their
+database connections for the meaning of "modify" in this paragraph.</p>
+
+<p>The progress handler callback would originally only be invoked from the
+bytecode engine. It still might be invoked during <a href="../c3ref/prepare.html">sqlite3_prepare()</a>
+and similar because those routines might force a reparse of the schema
+which involves running the bytecode engine. However, beginning with
+SQLite version 3.41.0, the progress handler callback might also be
+invoked directly from <a href="../c3ref/prepare.html">sqlite3_prepare()</a> while analyzing and generating
+code for complex queries.
+</p><p>See also lists of
+ <a href="../c3ref/objlist.html">Objects</a>,
+ <a href="../c3ref/constlist.html">Constants</a>, and
+ <a href="../c3ref/funclist.html">Functions</a>.</p>
+