switch
Code evaluation script which uses debug_backtrace() to get execution time in ns, relative current line number, function, file, and calling function info on each tick, and shove it all in $script_stats array. See debug_backtrace manual to customize what info is collected.
Warning: this will exhaust allowed memory very easily, so adjust tick counter according to the size of your code. Also, array_key_exists checking on debug_backtrace arrays is removed here only to keep this example simple, but should be added to avoid a large number of resulting PHP Notice errors.
<?php
$script_stats = array();
$time = microtime(true);
function track_stats(){
global $script_stats,$time;
$trace = debug_backtrace();
$exe_time = (microtime(true) - $time) * 1000;
$func_args = implode(", ",$trace[1]["args"]);
$script_stats[] = array(
"current_time" => microtime(true),
"memory" => memory_get_usage(true),
"file" => $trace[1]["file"].': '.$trace[1]["line"],
"function" => $trace[1]["function"].'('.$func_args.')',
"called_by" => $trace[2]["function"].' in '.$trace[2]["file"].': '.$trace[2]["line"],
"ns" => $exe_time
);
$time = microtime(true);
}
declare(ticks = 1);
register_tick_function("track_stats");
// the rest of your project code
// output $script_stats into a html table or something
?>
declare
declare 命令は、あるコードブロックの中に 実効命令をセットするために使用されます。declare の文法は他の制御構造と似ています。
declare (命令) 文
命令の箇所で、セットされた declareブロックの挙動を指定することが出来ます。 現在のところ、使用できる命令はticksの 一つだけです。( ticksに関しては以下を参照してください)
declareブロックの文 の実行のされ方や実行時にどのような作用が起こるかについては 命令に何が指定されたかに依存します。
declare構造はグローバルスコープしても使用され、 それはそれ以降のコード上の全てにおいて影響します。
<?php
// 以下は同じです:
// you can use this:
declare(ticks=1) {
// ここに全てのスクリプトを書く
}
// or you can use this:
declare(ticks=1);
// ここに全てのスクリプトを書く
?>
ticks
警告
PHP 5.3.0 で tick は非推奨となりました。 PHP 6.0.0 で削除される予定です。
tickとはdeclareブロックの実行中にパーサが N個の低レベル命令を実行するごとに 発生するイベントのことです。Nの値は declareブロックの命令の箇所で ticks=Nのように 指定します。
tickごとに発生させるイベントはregister_tick_function() を使用して指定します。詳細は以下の例を参照してください。1回のtickで 複数のイベントが起こり得ることに注意してください。
例1 PHPのコードの一部をプロファイルする
<pre>
<?php
// 呼び出されるとその時間を記録する関数
function profile ($dump = FALSE)
{
static $profile;
// 格納されたプロファイルを返し、その値を削除する
if ($dump) {
$temp = $profile;
unset($profile);
return $temp;
}
$profile[] = microtime();
}
// tickハンドラの設定
register_tick_function("profile");
// declareブロックの前で初期化しておく
profile ();
// 2命令ごとにtickを投げるように設定しブロックを実行する
declare (ticks=2) {
for ($x = 1; $x < 50; ++$x) {
echo similar_text (md5($x), md5($x*$x)), "<br />";
}
}
// プロファイラに格納されたデータを表示する
print_r (profile(TRUE));
?>
</pre>
ticksはデバッグ、単純なマルチタスク処理、バックグラウンドI/Oや その他多くの処理を実装するのに便利です。
register_tick_function()と unregister_tick_function()も参照してください。
add a note
User Contributed Notesdeclare
anotheruser at example dot com
23-Aug-2008 04:50
23-Aug-2008 04:50
zabmilenko at charter dot net
08-Jan-2008 01:49
08-Jan-2008 01:49
If you misspell the directive, you won't get any error or warning. The declare block will simply act as a nest for statements:
<?php
declare(tocks="four hundred")
{
// Has no affect on code and produces
// no error or warning.
}
?>
Tested in php 5.2.5 on XPsp2
rsemil at gmail dot com
06-Jan-2008 06:30
06-Jan-2008 06:30
rosen_ivanov's solution can be replaced by a simple call to memory_get_peak_usage() if you're running at least PHP 5.2.0
rosen_ivanov at abv dot bg
28-Aug-2006 06:06
28-Aug-2006 06:06
As Chris already noted, ticks doesn't make your script multi-threaded, but they are still great. I use them mainly for profiling - for example, placing the following at the very beginning of the script allows you to monitor its memory usage:
<?php
function profiler($return=false) {
static $m=0;
if ($return) return "$m bytes";
if (($mem=memory_get_usage())>$m) $m = $mem;
}
register_tick_function('profiler');
declare(ticks=1);
/*
Your code here
*/
echo profiler(true);
?>
This approach is more accurate than calling memory_get_usage only in the end of the script. It has some performance overhead though :)
aeolianmeson at NOSPAM dot blitzeclipse dot com
30-May-2006 12:06
30-May-2006 12:06
The scope of the declare() call if used without a block is a little unpredictable, in my experience. It appears that if placed in a method or function, it may not apply to the calls that ensue, like the following:
<?php
function a()
{
declare(ticks=2);
b();
}
function b()
{
// The declare may not apply here, sometimes.
}
?>
So, if all of a sudden the signals are getting ignored, check this. At the risk of losing the ability to make a mathematical science out of placing a number of activities at varying durations of ticks like many people have chosen to do, I've found it simple to just put this at the top of the code, and just make it global.
warhog at warhog dot net
18-Dec-2005 12:39
18-Dec-2005 12:39
as i read about ticks the first time i thought "wtf, useless crap" - but then i discovered some usefull application...
you can declare a tick-function which checks each n executions of your script whether the connection is still alive or not, very usefull for some kind of scripts to decrease serverload
<?php
function check_connection()
{ if (connection_aborted())
{ // do something here, e.g. close database connections
// (or use a shutdown function for this
exit; }
}
register_tick_function("connection");
declare (ticks=20)
{
// put your PHP-Script here
// you may increase/decrease the number of ticks
}
?>
chris-at-free-source.com
28-Feb-2005 12:16
28-Feb-2005 12:16
Also note that PHP is run in a single thread and so everything it does will be one line of code at a time. I'm not aware of any true threading support in PHP, the closest you can get is to fork.
so, declare tick doens't "multi-thread" at all, it is simply is a way to automaticaly call a function every n-lines of code.
fok at nho dot com dot br
07-Jul-2003 06:45
07-Jul-2003 06:45
This is a very simple example using ticks to execute a external script to show rx/tx data from the server
<?php
function traf(){
passthru( './traf.sh' );
echo "<br />\n";
flush(); // keeps it flowing to the browser...
sleep( 1 );
}
register_tick_function( "traf" );
declare( ticks=1 ){
while( true ){} // to keep it running...
}
?>
contents of traf.sh:
# Shows TX/RX for eth0 over 1sec
#!/bin/bash
TX1=`cat /proc/net/dev | grep "eth0" | cut -d: -f2 | awk '{print $9}'`
RX1=`cat /proc/net/dev | grep "eth0" | cut -d: -f2 | awk '{print $1}'`
sleep 1
TX2=`cat /proc/net/dev | grep "eth0" | cut -d: -f2 | awk '{print $9}'`
RX2=`cat /proc/net/dev | grep "eth0" | cut -d: -f2 | awk '{print $1}'`
echo -e "TX: $[ $TX2 - $TX1 ] bytes/s \t RX: $[ $RX2 - $RX1 ] bytes/s"
#--= the end. =--
daniel@swn
01-Feb-2003 11:56
01-Feb-2003 11:56
<?php
ob_end_clean();
ob_implicit_flush(1);
function a() {
for($i=0;$i<=100000;$i++) { }
echo "function a() ";
}
function b() {
for($i=0;$i<=100000;$i++) { }
echo "function b() ";
}
register_tick_function ("a");
register_tick_function ("b");
declare (ticks=4)
{
while(true)
{
sleep(1);
echo "\n<br><b>".time()."</b><br>\n";;
}
}
?>
You will see that a() and b() are slowing down this process. They are in fact not executed every second as expected. So this function is not a real alternative for multithreading using some slow functions..there is no difference to this way: while (true) { a(); b(); sleep(1); }
xxoes
08-Jan-2003 02:23
08-Jan-2003 02:23
If i use ticks i must declare all functions before i call the function.
example:
Dosn't work
<?php
function ticks() {
echo "tick";
}
register_tick_function("ticks");
declare (ticks=1) 1;
echo "";
echo "";
foo(); // Call to undefined function.
function foo() {
echo "foo";
}
?>
Work
<?php
function ticks() {
echo "tick";
}
register_tick_function("ticks");
//declare (ticks=1) 1;
echo "";
echo "";
foo();
function foo() {
echo "foo";
}
?>
win2k : PHP 4.3.0 (cgi-fcgi)
rob_spamsux at rauchmedien dot ihatespam dot com
19-Mar-2002 02:45
19-Mar-2002 02:45
Correction to above note:
Apparently, the end brace '}' at the end of the statement causes a tick.
So using
------------
declare (ticks=1) echo "1 tick after this prints";
------------
gives the expected behavior of causing 1 tick.
Note: the tick is issued after the statement executes.
Also, after playing around with this, I found that it is not really the multi-tasking I had expected. It behaves the same as simply calling the functions. I.e. each function must finish before passing the baton to the next function. They do not run in parallel.
It also seems that they always run in the order in which they were registered.
So,
<?php
------------
# register tick functions
register_tick_function ("a");
register_tick_function ("b");
# make the tick functions run
declare (ticks=1);
?>
------------
is equivalent to
------------
a();
b();
------------
It is simply a convenient way to have functions called periodically while some other code is being executed. I.e. you could use it to periodically check the status of something and then exit the script or do something else based on the status.
rob_spamsux at rauchmedien dot ihatespam dot com
19-Mar-2002 01:58
19-Mar-2002 01:58
Here is an example of multi-tasking / multi-threading:
<?php
# declare functions
function a() {
echo "a";
}
function b() {
echo "b";
}
# register tick functions
register_tick_function ("a");
register_tick_function ("b");
# make the tick functions run
declare (ticks=1);
# that's all there is to it.
?>
Notes:
This will make functions a and b run once each at the same time.
If you try:
declare (ticks=1) {
1;
}
They will run twice each. That is because it seems to be an undocumented fact that there is always an extra tick.
Therefore:
declare (ticks=2) {
1;
}
Will cause them to run once.