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 $script_stats into a html table or something
?>
declare
O construtor declare é utilizado para configurar diretivas de execução para blocos de código. A sintaxe do declare é similar a sintaxe de outros construtores de controle.
declare (diretiva) instrucao
A seção diretiva permite o comportamento do bloco declare a ser configurado. Atualmente somente uma diretiva é reconhecida: a diretiva ticks. (veja abaixo para maiores informações em diretiva ticks)
A parte instrucao do bloco declare será executada. Como ela é executada e que efeitos colaterais que podem ocorrem durante a execução dependem da configuração diretiva.
O construtor declare também pode ser utilizado no escopo global, afetando todo o código que se seguir.
<?php
// isso eh o mesmo:
// voce pode fazer isso:
declare(ticks=1) {
// script inteiro aqui
}
// ou pode fazer isto:
declare(ticks=1);
// sctipt inteiro aqui
?>
Ticks
Um tick é um evento que ocorre para cada
N níveis de instruções executados
pelo interpretador com o bloco declare.
O valor para N é especificado
utilizando ticks=N
nos blocos declare das
seções diretiva.
O(s) evento(s) que ocorre(m) em cada tick são especificados utilizando register_tick_function(). Veja o exemplo abaixo para maiores detalhes. Note que mais de um evento pode ocorrer em cada tick.
Exemplo #1 Histórico de um trecho de código PHP
<?php
// Uma função que grava o tempo entre as chamadas
function profile ($dump = FALSE)
{
static $profile;
// Retorna os tempos preservados no histórico, então apaga
if ($dump) {
$temp = $profile;
unset ($profile);
return $temp;
}
$profile[] = microtime ();
}
// Ativa o manipulador do tick
register_tick_function("profile");
// Inicializa a função antes de declarar o bloco
profile();
// Roda um trecho de código, disparando um tick a cada duas instruções
declare(ticks=2) {
for ($x = 1; $x < 50; ++$x) {
echo similar_text(md5($x), md5($x*$x)), "<br />;";
}
}
// Mostra os dados guardados no histórico
print_r(profile (TRUE));
?>
Ticks são idealizados para debug, implementação de multitask simples, processos de I/O em background e afins.
Veja também: register_tick_function() e unregister_tick_function().
add a note
User Contributed Notesdeclare
anotheruser at example dot com
23-Aug-2008 05:50
23-Aug-2008 05:50
zabmilenko at charter dot net
08-Jan-2008 02:49
08-Jan-2008 02:49
If you misspell the directive, you won't get any error or warning. The declare block will simply act as a nest for statements:
<?php
declare(tocks="four hundred")
{
// Has no affect on code and produces
// no error or warning.
}
?>
Tested in php 5.2.5 on XPsp2
rsemil at gmail dot com
06-Jan-2008 07:30
06-Jan-2008 07:30
rosen_ivanov's solution can be replaced by a simple call to memory_get_peak_usage() if you're running at least PHP 5.2.0
rosen_ivanov at abv dot bg
28-Aug-2006 07:06
28-Aug-2006 07:06
As Chris already noted, ticks doesn't make your script multi-threaded, but they are still great. I use them mainly for profiling - for example, placing the following at the very beginning of the script allows you to monitor its memory usage:
<?php
function profiler($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 01:06
30-May-2006 01:06
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 01:39
18-Dec-2005 01:39
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 01:16
28-Feb-2005 01:16
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 07:45
07-Jul-2003 07:45
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 - $RX1 ] bytes/s"
#--= the end. =--
daniel@swn
01-Feb-2003 12:56
01-Feb-2003 12:56
<?php
ob_end_clean();
ob_implicit_flush(1);
function a() {
for($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 03:23
08-Jan-2003 03:23
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 03:45
19-Mar-2002 03:45
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 02:58
19-Mar-2002 02:58
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.