<?php
class Foo {
    function bar($str)
    {   
        return $str.'bar';
    }
}
function baz($str) {
    return $str."baz\n";
}
$foo = new Foo;
ob_start('baz');
ob_start(array(&$foo, 'bar'));
print 'foo';
?>

This script fails to add 'bar' to the string on every machine when using PHP5, and it segfaults on mine.

et@edea:~$ /usr/local/sources/php-4.3.1/sapi/cli/php test.php 
foobarbaz
et@edea:~$ /usr/local/sources/unstable/php5-200305031330/sapi/cli/php test.php 
Segmentation fault (core dumped)


Backtrace is:

(gdb) bt
#0  0x0816d425 in zend_hash_index_find (ht=0x0, h=0, pData=0x0)
    at /home/et/sources/unstable/php5-200305031330/Zend/zend_hash.c:979
#1  0x08160a02 in call_user_function_ex (function_table=0x828d128, object_pp=0x0, function_name=0x4026d0b4, 
    retval_ptr_ptr=0xbfffe4e0, param_count=2, params=0xbfffe4e8, no_separation=1, symbol_table=0x0)
    at /home/et/sources/unstable/php5-200305031330/Zend/zend_execute_API.c:555
#2  0x081467c9 in php_end_ob_buffer (send_buffer=1 '\001', just_flush=0 '\0')
    at /home/et/sources/unstable/php5-200305031330/main/output.c:241
#3  0x0814693b in php_end_ob_buffers (send_buffer=0 '\0')
    at /home/et/sources/unstable/php5-200305031330/main/output.c:335
#4  0x0813bc8c in php_request_shutdown (dummy=0x0) at /home/et/sources/unstable/php5-200305031330/main/main.c:1091
#5  0x08181368 in main (argc=2, argv=0xbfffec64) at /home/et/sources/unstable/php5-200305031330/sapi/cli/php_cli.c:1006
#6  0x420158d4 in __libc_start_main () from /lib/i686/libc.so.6
(gdb) 

config.nice:
#! /bin/sh
#
# Created by configure

'./configure' \
'--enable-bcmath' \
'--with-gmp' \
'--with-mysql' \
'--with-pgsql' \
'--enable-calendar' \
'--with-apxs=/opt/apache/1.3.27/bin/apxs' \
'--with-zlib' \
'--with-bz2' \
'--with-config-file-path=/home/et' \
'--with-openssl' \
'--enable-debug' \
"$@"

I know the config file path is odd, i just use the machine for developing and i'm the only one working on it ;)