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  [2009-12-15 13:27 UTC] lesjno at free dot fr
 Description:
------------
Memory used by the eval() function is not null and can be important (up to 8Ko) especially if the string is not evaluable.
This memory used can't be released. 
Used in a big loop, the memory used is growing up and I get a memory error.
Reproduce code:
---------------
$result="";
$memory_used1 = memory_get_usage();
$ch="\$result=22;"; if (@eval($ch)===false) {$result = $ch ;}
$memory_used2 = memory_get_usage();
echo "result=$result ==><b>memory difference = ".($memory_used2-$memory_used1)."<BR></b>\n";
$memory_used1 = memory_get_usage();
$ch="abcdef"; if (@eval($ch)===false) {$result = $ch ;}
$memory_used2 = memory_get_usage();
echo "result=$result ==><b>memory difference = ".($memory_used2-$memory_used1)."<BR></b>\n";
 
Expected result:
----------------
result=22 ==>memory difference = 0
result=abcdef ==>memory difference = 0
Actual result:
--------------
result=22 ==>memory difference = 200
result=abcdef ==>memory difference = 7480
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        Last updated: Tue Nov 04 02:00:01 2025 UTC | 
Hello jani, I have a loop to update a database from an excel file. So, for each excel row I will apply several tests and initializations specified in a configuration file. The configuration file depend on the user profile. The eval() function is used, for example, for data initialization : the configuration file can give a data or a code. For example a specific date field can take a fix date ("2009-01-01") or can be computed. So, for example, I can found in a configuration file : for a user category : $field_init = '2009-01-01' ; for another user category : $field_init = 'return date("Y-m-d");' ; I will use the following code : $data = @eval($field_init) ; if ($data===false) $data=$field_init; It's only an example but there are a lot of others "eval()" like this for each excel row treatment. An excel file can have more than 50000 rows ... so the memory leak is growing up till the system error ...PHP Versions: ------------- Tested as broken with 5.2.6 5.3.2 Reproduce code: --------------- <?php // working code, runs for ever $code = 'return false;'; while(true) { $result = eval($code); $mem = memory_get_peak_usage(true); var_dump($result, $mem); } <?php // broken code, dies due to memory limit being reached $code = 'some invalid php code'; while(true) { $result = eval($code); $mem = memory_get_peak_usage(true); var_dump($result, $mem); } Expected result: ---------------- A var_dump of false and the peak memory usage, not increasing. Actual result: -------------- A var_dump of false and the peak memory usage keeps increasing.