Installing Xdebug
pear -v install http://files.derickrethans.nl/xdebug-1.3.0.tgz
+ create dir /usr/local/lib/php/docs/xdebug
52 source files, building
building in /tmp/tmpH4fmdM/xdebug-1.3.0
running: phpize
Configuring for:
  PHP Api Version:   20020918
  Zend Module Api No:   20020429
  Zend Extension Api No:   20021010
building in /var/tmp/pear-build-root/xdebug-1.3.0
running: /tmp/tmpH4fmdM/xdebug-1.3.0/configure
checking build system type... i686-redhat-linux-gnu
checking host system type... i686-redhat-linux-gnu
checking for gcc... gcc
checking for C compiler default output... a.out
...
Build process completed successfully
Installing 'xdebug.so' at ext_dir (/usr/local/lib/php/extensions/no-debug-non-zts-20020429/xdebug.so)
about to commit 16 file operations
successfully committed 16 file operations
install ok: xdebug 1.3.0
Stack trace
<?php
    $GLOBALS['trace'] = xdebug_start_trace('/tmp/xdebug.trace',true);
    function a() {
        b();
    }
    function b() {
        echo "<pre>";
        readfile($GLOBALS['trace']);
        echo "</pre>";
    }
    a();
    xdebug_stop_trace();
?>
Output