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debug_backtrace (PHP 4 >= 4.3.0, PHP 5) debug_backtrace -- Generates a backtrace Описаниеarray debug_backtrace ( void )
debug_backtrace() generates a PHP backtrace.
Возвращаемые значения
Returns an associative array. The possible returned elements
are as follows:
Таблица 1. Possible returned elements from debug_backtrace() | Name | Type | Description |
|---|
| function | string |
The current function name. See also
__FUNCTION__.
| | line | integer |
The current line number. See also
__LINE__.
| | file | string |
The current file name. See also
__FILE__.
| | class | string |
The current class name. See also
__CLASS__
| | object | object |
The current object.
| | type | string |
The current call type. If a method call, "->" is returned. If a static
method call, "::" is returned. If a function call, nothing is returned.
| | args | array |
If inside a function, this lists the functions arguments. If
inside an included file, this lists the included file name(s).
|
Примеры
Пример 1. debug_backtrace() example |
<?php
function a_test($str)
{
echo "\nHi: $str";
var_dump(debug_backtrace());
}
a_test('friend');
?>
<?php
include_once '/tmp/a.php';
?>
|
Results similar to the following when executing
/tmp/b.php:
Hi: friend
array(2) {
[0]=>
array(4) {
["file"] => string(10) "/tmp/a.php"
["line"] => int(10)
["function"] => string(6) "a_test"
["args"]=>
array(1) {
[0] => &string(6) "friend"
}
}
[1]=>
array(4) {
["file"] => string(10) "/tmp/b.php"
["line"] => int(2)
["args"] =>
array(1) {
[0] => string(10) "/tmp/a.php"
}
["function"] => string(12) "include_once"
}
} |
|
misterpib at gmail dot com
17-Oct-2007 09:35
You should probably try to avoid changing any of the items in the args array. Consider this example:
----------
function a(&$value)
{
echo "start a: $value\n";
b();
echo "end a: $value\n";
}
function b()
{
echo "start b\n";
$stack = debug_backtrace();
$stack[1]['args'][0] = 'bob';
echo "end b\n";
}
$mynum = 42;
a($mynum);
--------------
This prints:
start a: 42
start b
end b
end a: bob
php at kennel17 dot co dot uk
20-Jun-2007 09:30
Further to my previous note, the 'object' element of the array can be used to get the parent object. So changing the get_class_static() function to the following will make the code behave as expected:
<?php
function get_class_static() {
$bt = debug_backtrace();
if (isset($bt[1]['object']))
return get_class($bt[1]['object']);
else
return $bt[1]['class'];
}
?>
HOWEVER, it still fails when being called statically. Changing the last two lines of my previous example to
<?php
foo::printClassName();
bar::printClassName();
?>
...still gives the same problematic result in PHP5, but in this case the 'object' property is not set, so that technique is unavailable.
php at kennel17 dot co dot uk
20-Jun-2007 09:01
The value of the class argument has changed slightly between PHP4 and PHP5:
Here's an example:
<?php
function get_class_static() {
$bt = debug_backtrace();
$name = $bt[1]['class'];
return $name;
}
class foo {
function printClassName() {
print(get_class_static() . "\n");
}
}
class bar extends foo {
}
$f = new foo();
$b = new bar();
$f->printClassName();
$b->printClassName();
?>
In PHP4 you get:
foo
bar
In PHP5 you get:
foo
foo
debug_backtrace() now sets the 'class' parameter to be the class that the function is actually defined in, not the name of the instantiated class.
jsnell at e-normous dot com
30-May-2007 02:35
If you are using the backtrace function in an error handler, avoid using var_export() on the args, as you will cause fatal errors in some situations, preventing you from seeing your stack trace. Some structures will cause PHP to generate the fatal error "Nesting level too deep - recursive dependency?" This is a design feature of php, not a bug (see http://bugs.php.net/bug.php?id=30471)
kroczu AT interia DOT pl
23-Jan-2007 10:24
<?
// useful and comfortable debug function
// it's show memory usage and time flow between calls, so we can quickly find a block of code that need optimisation...
// example result:
/*
debug example.php> initialize
debug example.php> code-lines: 39-41 time: 2.0002 mem: 19 KB
debug example.php> code-lines: 41-44 time: 0.0000 mem: 19 KB
debug example.php> code-lines: 44-51 time: 0.6343 mem: 9117 KB
debug example.php> code-lines: 51-53 time: 0.1003 mem: 9117 KB
debug example.php> code-lines: 53-55 time: 0.0595 mem: 49 KB
*/
function debug()
{
static $start_time = NULL;
static $start_code_line = 0;
$call_info = array_shift( debug_backtrace() );
$code_line = $call_info['line'];
$file = array_pop( explode('/', $call_info['file']));
if( $start_time === NULL )
{
print "debug ".$file."> initialize\n";
$start_time = time() + microtime();
$start_code_line = $code_line;
return 0;
}
printf("debug %s> code-lines: %d-%d time: %.4f mem: %d KB\n", $file, $start_code_line, $code_line, (time() + microtime() - $start_time), ceil( memory_get_usage()/1024));
$start_time = time() + microtime();
$start_code_line = $code_line;
}
////////////////////////////////////////////////
// example:
debug();
sleep(2);
debug();
// soft-code...
$a = 3 + 5;
debug();
// hard-code
for( $i=0; $i<100000; $i++)
{
$dummy['alamakota'.$i] = 'alamakota'.$i;
}
debug();
usleep(100000);
debug();
unset($dummy);
debug();
?>
seaside dot ki at mac dot com
14-Dec-2006 04:20
I've started creating an external debug server for PHP. A PHP app require_once's a TADebugger(), which communicates with the debug sever. Find the OS X universal binary here [PHP source sample included]:
http://www.turingart.com/downloads/phpDebugger.zip
Currently, TADebugger allows to post these properties back to the debug server:
- Call backtraces
- String messages
- Source files, which were referenced by a backtrace call
Note, that the binary is a early version.
icefragment at gmail dot com
23-Sep-2006 09:34
A simple python-like backtrace. Note that I don't recurse into arrays if they are passed as arguments to functions.
function backtrace()
{
$bt = debug_backtrace();
echo("<br /><br />Backtrace (most recent call last):<br /><br />\n");
for($i = 0; $i <= count($bt) - 1; $i++)
{
if(!isset($bt[$i]["file"]))
echo("[PHP core called function]<br />");
else
echo("File: ".$bt[$i]["file"]."<br />");
if(isset($bt[$i]["line"]))
echo(" line ".$bt[$i]["line"]."<br />");
echo(" function called: ".$bt[$i]["function"]);
if($bt[$i]["args"])
{
echo("<br /> args: ");
for($j = 0; $j <= count($bt[$i]["args"]) - 1; $j++)
{
if(is_array($bt[$i]["args"][$j]))
{
print_r($bt[$i]["args"][$j]);
}
else
echo($bt[$i]["args"][$j]);
if($j != count($bt[$i]["args"]) - 1)
echo(", ");
}
}
echo("<br /><br />");
}
}
zmorris at mac dot com
20-Sep-2006 07:48
Hi, I got tired of using a trace( $message, __FILE__, __LINE__ ) function I made. It forced me to include the file and line params (since php doesn't have macros) so I decided to make an alternative.
Simply call this new version using trace( 'my message' ); and it prints out a stack trace in a clearer way than the one stored in the debug_backtrace() array. It handles traces from outside of functions, traces in nested functions, and traces in included files, and also displays the function in a way that can be pasted right back into your php code for faster testing!
NOTE - be sure to save your files with the correct line endings for the line numbers to work correctly, which for Mac OS X is unix. You can get to this option in the popup menu in the toolbar at the top of each window in BBEdit.
<?php
function print_var( $var )
{
if( is_string( $var ) )
return( '"'.str_replace( array("\x00", "\x0a", "\x0d", "\x1a", "\x09"), array('\0', '\n', '\r', '\Z', '\t'), $var ).'"' );
else if( is_bool( $var ) )
{
if( $var )
return( 'true' );
else
return( 'false' );
}
else if( is_array( $var ) )
{
$result = 'array( ';
$comma = '';
foreach( $var as $key => $val )
{
$result .= $comma.print_var( $key ).' => '.print_var( $val );
$comma = ', ';
}
$result .= ' )';
return( $result );
}
return( var_export( $var, true ) ); }
function trace( $msg )
{
echo "<pre>\n";
$trace = array_reverse( debug_backtrace() );
$indent = '';
$func = '';
echo $msg."\n";
foreach( $trace as $val)
{
echo $indent.$val['file'].' on line '.$val['line'];
if( $func ) echo ' in function '.$func;
if( $val['function'] == 'include' ||
$val['function'] == 'require' ||
$val['function'] == 'include_once' ||
$val['function'] == 'require_once' )
$func = '';
else
{
$func = $val['function'].'(';
if( isset( $val['args'][0] ) )
{
$func .= ' ';
$comma = '';
foreach( $val['args'] as $val )
{
$func .= $comma.print_var( $val );
$comma = ', ';
}
$func .= ' ';
}
$func .= ')';
}
echo "\n";
$indent .= "\t";
}
echo "</pre>\n";
}
trace( 'error outside function' );
function test( $param1, $param2, $param3, $param4 )
{
trace( 'error in test()' );
}
test( 1.1, "param2\n", array( 1 => "a\n", "b\n" => 2 ), false );
?>
admin at sgssweb dot com
13-Aug-2006 02:30
Surprizingly, debug_backtrace() cannot aquire arguments from the function that is used as the second or later argument of a function.
<?php
function a($p) {
$backtrace = debug_backtrace();
if (isset($backtrace[0]['args']))
var_export($backtrace[0]['args']);
else
echo "Cannot aquire arguments";
echo "<br />";
return $p;
}
function b($p1, $p2, $p3) {
echo "$p1, $p2, $p3";
}
b(a("First a"), a("Second a"), a("Third a"));
?>
tiwen at rpgame dot de
30-Apr-2006 01:25
Another debug output. This is a short function that does not display the args (sometimes password are in arguments ...) and shows the callstack clearly in a table. In most cases i don't need more ...
<?php
function dieDebug($sError)
{
echo "<hr /><div>".$sError."<br /><table border='1'>";
$sOut=""; $aCallstack=debug_backtrace();
echo "<thead><tr><th>file</th><th>line</th><th>function</th>".
"</tr></thead>";
foreach($aCallstack as $aCall)
{
if (!isset($aCall['file'])) $aCall['file'] = '[PHP Kernel]';
if (!isset($aCall['line'])) $aCall['line'] = '';
echo "<tr><td>{$aCall["file"]}</td><td>{$aCall["line"]}</td>".
"<td>{$aCall["function"]}</td></tr>";
}
echo "</table></div><hr /></p>";
die();
}
?>
To use it, simply do something like this:
<?php
if(...) dieDebug("another error found!");
?>
http://synergy8.com
13-Dec-2005 10:37
It should be noted that if an internal php function such as call_user_func in the backtrace, the 'file' and 'line' entries will not be set.
Most debug tracers will use these entries. You should place a check to see if the key exists in the array before using this function. Otherwise notices will be generated.
<?php
$arrTrace = debug_backtrace();
foreach ($arrTrace as $arr)
{
if (!isset ($arr['file']))
{
$arr['file'] = '[PHP Kernel]';
}
if (!isset ($arr['line']))
{
$arr['line'] = '';
}
}
?>
tb
21-Jul-2005 11:18
I use this for debugging in my object oriented systems. It allows me to output a debug/error/warning function with exact information about the location that the error was thrown, which is useful. Check it:
<?php
abstract class Debugger {
abstract function debug($msg);
abstract function error($msg);
abstract function warning($msg);
protected function getMsg($msg) {
$bt = debug_backtrace();
$class = $bt[2]['class'];
$function = $bt[2]['function'];
$file = $bt[1]['file'];
$line = $bt[1]['line'];
return "$class::$function: $msg in $file at $line";
}
}
?>
Implement different debuggers for different scenarios (development, testing, production). Each debugger extends Debugger; each of its methods (debug/error/warning) calls $this->getMsg($msg) to get a message with class, function, file, and line information. Then it can either log it, email it, die with it, etc.
Then, just give each object (perhaps using a common superclass Object) a concrete debugger. Then, from any object method, do something like:
<?php
class Foo extends Object {
function bar() {
$this->debugger->error("This is an error");
}
}
?>
Which produces something like:
Foo::bar: This is an error in /some/file at X
diz at ysagoon dot com
24-Nov-2004 02:35
Ok as spagmoid already said, I just realized that my function has a similar bug than jlim's function.
So just add the following line:
if (is_array($bt['args']))
before line:
foreach ($bt['args'] as $a) {
This way you avoid the warning from being displayed.
diz at ysagoon dot com
23-Nov-2004 02:40
And here are my two cents for a useful and good looking backtrace function.
<?php
function backtrace()
{
$output = "<div style='text-align: left; font-family: monospace;'>\n";
$output .= "<b>Backtrace:</b><br />\n";
$backtrace = debug_backtrace();
foreach ($backtrace as $bt) {
$args = '';
foreach ($bt['args'] as $a) {
if (!empty($args)) {
$args .= ', ';
}
switch (gettype($a)) {
case 'integer':
case 'double':
$args .= $a;
break;
case 'string':
$a = htmlspecialchars(substr($a, 0, 64)).((strlen($a) > 64) ? '...' : '');
$args .= "\"$a\"";
break;
case 'array':
$args .= 'Array('.count($a).')';
break;
case 'object':
$args .= 'Object('.get_class($a).')';
break;
case 'resource':
$args .= 'Resource('.strstr($a, '#').')';
break;
case 'boolean':
$args .= $a ? 'True' : 'False';
break;
case 'NULL':
$args .= 'Null';
break;
default:
$args .= 'Unknown';
}
}
$output .= "<br />\n";
$output .= "<b>file:</b> {$bt['line']} - {$bt['file']}<br />\n";
$output .= "<b>call:</b> {$bt['class']}{$bt['type']}{$bt['function']}($args)<br />\n";
}
$output .= "</div>\n";
return $output;
}
?>
And here's a sample of how the output looks like (the last call is on the top):
Backtrace:
file: 56 - /tmp/test.php
call: backtrace()
file: 53 - /tmp/test.php
call: test->bar(15.4, Array(4))
file: 61 - /tmp/test.php
call: test->test("making new object", True)
file: 65 - /tmp/test.php
call: foo(Resource(#2), Null)
ad-rotator.com
30-Apr-2004 09:11
To simply print out the file/function trace (chain of calls, file and line number before the error):
function getTrace() {
$vDebug = debug_backtrace();
$vFiles = array();
for ($i=0;$i<count($vDebug);$i++) {
// skip the first one, since it's always this func
if ($i==0) { continue; }
$aFile = $vDebug[$i];
$vFiles[] = '('.basename($aFile['file']).':'.$aFile['line'].')';
} // for
$vTraceStr = implode(',',$vFiles);
}
spagmoid at yahoo dot NOSPAMcom
09-Dec-2003 11:47
ATTN: jlim#natsoft.com.my
Great function, but you have a few bugs.
At the line:
foreach($arr['args'] as $v)
Change it to:
$args = array();
if(!empty($arr['args'])) foreach($arr['args'] as $v)
And since line & file are not present in the array if calling from the error handler,
$Line = (isset($arr['line'])? $arr['line'] : "unknown");
$File = (isset($arr['file'])? $arr['file'] : "unknown");
and substitute accordingly.
Here's my version of it, alas with different formatting:
----------------------------------------
function DBG_GetBacktrace()
{
$s = '';
$MAXSTRLEN = 64;
$s = '<pre align=left>';
$traceArr = debug_backtrace();
array_shift($traceArr);
$tabs = sizeof($traceArr)-1;
foreach($traceArr as $arr)
{
for ($i=0; $i < $tabs; $i++) $s .= ' ';
$tabs -= 1;
$s .= '<font face="Courier New,Courier">';
if (isset($arr['class'])) $s .= $arr['class'].'.';
$args = array();
if(!empty($arr['args'])) foreach($arr['args'] as $v)
{
if (is_null($v)) $args[] = 'null';
else if (is_array($v)) $args[] = 'Array['.sizeof($v).']';
else if (is_object($v)) $args[] = 'Object:'.get_class($v);
else if (is_bool($v)) $args[] = $v ? 'true' : 'false';
else
{
$v = (string) @$v;
$str = htmlspecialchars(substr($v,0,$MAXSTRLEN));
if (strlen($v) > $MAXSTRLEN) $str .= '...';
$args[] = "\"".$str."\"";
}
}
$s .= $arr['function'].'('.implode(', ',$args).')</font>';
$Line = (isset($arr['line'])? $arr['line'] : "unknown");
$File = (isset($arr['file'])? $arr['file'] : "unknown");
$s .= sprintf("<font color=#808080 size=-1> # line %4d, file: <a href=\"file:/%s\">%s</a></font>",
$Line, $File, $File);
$s .= "\n";
}
$s .= '</pre>';
return $s;
}
Fabian dot Kraetzer at gmx dot de
01-Sep-2003 06:18
I coded a function, too. Just call debug() evertime you think you could encounter an error:
<?
function debug()
{
$debug_array = debug_backtrace();
$counter = count($debug_array);
for($tmp_counter = 0; $tmp_counter != $counter; ++$tmp_counter)
{
?>
<table width="558" height="116" border="1" cellpadding="0" cellspacing="0" bordercolor="#000000">
<tr>
<td height="38" bgcolor="#D6D7FC"><font color="#000000">function <font color="#FF3300"><?
echo($debug_array[$tmp_counter]["function"]);?>(</font> <font color="#2020F0"><?
//count how many args a there
$args_counter = count($debug_array[$tmp_counter]["args"]);
//print them
for($tmp_args_counter = 0; $tmp_args_counter != $args_counter; ++$tmp_args_counter)
{
echo($debug_array[$tmp_counter]["args"][$tmp_args_counter]);
if(($tmp_args_counter + 1) != $args_counter)
{
echo(", ");
}
else
{
echo(" ");
}
}
?></font><font color="#FF3300">)</font></font></td>
</tr>
<tr>
<td bgcolor="#5F72FA"><font color="#FFFFFF">{</font><br>
<font color="#FFFFFF"> file: <?
echo($debug_array[$tmp_counter]["file"]);?></font><br>
<font color="#FFFFFF"> line: <?
echo($debug_array[$tmp_counter]["line"]);?></font><br>
<font color="#FFFFFF">}</font></td>
</tr>
</table>
<?
if(($tmp_counter + 1) != $counter)
{
echo("<br>was called by:<br>");
}
}
exit();
}
?>
bernyregeling AT hotmail DOT com
08-Aug-2003 04:29
I wrote this function, in addition to jlim, for a nice NO-HTML output.
Thee result has similarities to a Java-error. Hope you like it.
(BTW, this function exits the script too, if debug_backtrace is displayed)
------------------------------
function debug_bt()
{
if(!function_exists('debug_backtrace'))
{
echo 'function debug_backtrace does not exists'."\r\n";
return;
}
//echo '<pre>';
echo "\r\n".'----------------'."\r\n";
echo 'Debug backtrace:'."\r\n";
echo '----------------'."\r\n";
foreach(debug_backtrace() as $t)
{
echo "\t" . '@ ';
if(isset($t['file'])) echo basename($t['file']) . ':' . $t['line'];
else
{
// if file was not set, I assumed the functioncall
// was from PHP compiled source (ie XML-callbacks).
echo '<PHP inner-code>';
}
echo ' -- ';
if(isset($t['class'])) echo $t['class'] . $t['type'];
echo $t['function'];
if(isset($t['args']) && sizeof($t['args']) > 0) echo '(...)';
else echo '()';
echo "\r\n";
}
//echo '</pre>';
exit;
}
jlim#natsoft.com.my
13-Mar-2003 05:51
Pretty print the backtrace(). Functions are indented based on call value, and file is linked using file:// for convenience.
Enjoy, John Lim
function adodb_backtrace($print=true)
{
$s = '';
if (PHPVERSION() >= 4.3) {
$MAXSTRLEN = 64;
$s = '<pre align=left>';
$traceArr = debug_backtrace();
array_shift($traceArr);
$tabs = sizeof($traceArr)-1;
foreach ($traceArr as $arr) {
for ($i=0; $i < $tabs; $i++) $s .= ' ';
$tabs -= 1;
$s .= '<font face="Courier New,Courier">';
if (isset($arr['class'])) $s .= $arr['class'].'.';
foreach($arr['args'] as $v) {
if (is_null($v)) $args[] = 'null';
else if (is_array($v)) $args[] = 'Array['.sizeof($v).']';
else if (is_object($v)) $args[] = 'Object:'.get_class($v);
else if (is_bool($v)) $args[] = $v ? 'true' : 'false';
else {
$v = (string) @$v;
$str = htmlspecialchars(substr($v,0,$MAXSTRLEN));
if (strlen($v) > $MAXSTRLEN) $str .= '...';
$args[] = $str;
}
}
$s .= $arr['function'].'('.implode(', ',$args).')';
$s .= sprintf("</font><font color=#808080 size=-1> # line %4d,".
" file: <a href=\"file:/%s\">%s</a></font>",
$arr['line'],$arr['file'],$arr['file']);
$s .= "\n";
}
$s .= '</pre>';
if ($print) print $s;
}
return $s;
}
|
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