PHP Velho Oeste 2024

PHP Callbacks

It is possible to assign a PHP closure to a native variable of function pointer type or to pass it as a function argument:

<?php
$zend
= FFI::cdef("
typedef int (*zend_write_func_t)(const char *str, size_t str_length);
extern zend_write_func_t zend_write;
"
);

echo
"Hello World 1!\n";

$orig_zend_write = clone $zend->zend_write;
$zend->zend_write = function($str, $len) {
global
$orig_zend_write;
$orig_zend_write("{\n\t", 3);
$ret = $orig_zend_write($str, $len);
$orig_zend_write("}\n", 2);
return
$ret;
};
echo
"Hello World 2!\n";
$zend->zend_write = $orig_zend_write;
echo
"Hello World 3!\n";
?>

上の例の出力は以下となります。

Hello World 1!
{
        Hello World 2!
}
Hello World 3!
Although this works, this functionality is not supported on all libffi platforms, is not efficient and leaks resources by the end of request.
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It is therefore recommended to minimize the usage of PHP callbacks.

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