Something

--TEST--
assert() - set callback using ini.set
--INI--
error_reporting = 2039
--FILE--
<?php
function a($file,$line,$myev)
{ 
	echo "assertion failed - a - $line,\"$myev\"\n";
}

function b($file,$line,$myev)
{ 
	echo "assertion failed - b - $line,\"$myev\"\n";
}

assert_options(ASSERT_ACTIVE,1);
assert_options(ASSERT_QUIET_EVAL,1);
assert_options(ASSERT_WARNING,0);

$a = 0;

assert_options(ASSERT_CALLBACK,"a");
assert('$a != 0');

 /* Modify call back using ini_set() */
ini_set("assert.callback", "b");
assert('$a != 0');

?>

--EXPECTF--
assertion failed - a - %d,"$a != 0"
assertion failed - b - %d,"$a != 0"