PHP Callbacks
PHP Callbacks
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";
?>The above example will output:
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.
Tip
It is therefore recommended to minimize the
usage of PHP callbacks.