Debugging PHP

[Dave Moore]

Hi All,
I've just started writing PHP scripts. I was wondering whether there was
any sensible debugging facilities that I'm not aware of. Basically, my usual
development procedure involves writing the script and then testing using IE.
However, it appears that unless the PHP is perfect (ie. devoid of any
syntactical errors) then nothing at all is output to the browser. Personally
I find this very frustrating as there's no clue as to where the error is. I
then commence on a wild goose chase putting in various debugging 'echo'
statements and commenting out various chunks of PHP code until something
works. There must be a better approach than this.

Are there any option or selections I can make to give me some debugging
output?. Is there a parser I can use to ensure there are no syntactical
errors before running the script?. Or a PHP debugger I can use to step
through the code command by command?.

Thanks,
Dave

[Philip Ronan]

Dave Moore wrote:

Are there any option or selections I can make to give me some debugging
output?

Put this at the top of your PHP script:

error_reporting (E_ALL);

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http://vzone.virgin.net/phil.ronan/

[justbn]

Dave,

Putting error_reporting (E_ALL) directly in your script may not be
necessary. By default, this value is already set in PHP. Use
phpinfo() to find out if it is.

Your best bet is to put in echo, print, or fwrite(for command line
interface) in your script at key points. This will help you "walk"
through it.

There are several IDE's that have debugging capabilities. They may
even be able to run the script or step through it.

There is a free IDE for PHP (http://syn.sourceforge.net/). It is a
decent editor with Syntax highlighting and the such. It also has
debugging capabilities. However, I never had luck getting this aspect
to work and gave up on it. But, it is a decent editor. I would not
that it seems to be a bit of a process and memory hog at random times.

[Henk Verhoeven]

Hi Dave,

The following is not a debugger, but it can be very helpfull nevertheless:
http://nl2.php.net/manual/en/functio...-backtrace.php
feed the array to print_r to see what exactly you get. Then it should
not be hard to build a fancy backtrace printing function.

If you make an error handling function and set its name with
set_error_handl er you can make it print a backtrace below the
coventional error info. (search the manual for set_error_handl er)

Limitation: it will not work for fatal errors - imho the person that
decided that php developers do not need error handling for fatal errors
made a fatal mistake :-(((

Greetings,

Henk Verhoeven,
www.phpPeanuts.org.

Dave Moore wrote:

Hi All,
I've just started writing PHP scripts. I was wondering whether there was
any sensible debugging facilities that I'm not aware of. Basically, my usual
development procedure involves writing the script and then testing using IE.
However, it appears that unless the PHP is perfect (ie. devoid of any
syntactical errors) then nothing at all is output to the browser. Personally
I find this very frustrating as there's no clue as to where the error is. I
then commence on a wild goose chase putting in various debugging 'echo'
statements and commenting out various chunks of PHP code until something
works. There must be a better approach than this.

Are there any option or selections I can make to give me some debugging
output?. Is there a parser I can use to ensure there are no syntactical
errors before running the script?. Or a PHP debugger I can use to step
through the code command by command?.

Thanks,
Dave

[Chung Leong]

That won't help when there's a parse error. The solution here is to
make sure display_error is set to "on" in php.ini and error_reporting
to something sensible, like E_ALL & ~E_NOTICE.

[Andy Hassall]

On 30 Apr 2005 11:26:43 -0700, "Chung Leong <ch***********@ hotmail.com>"
<ch***********@ hotmail.com> wrote:

That won't help when there's a parse error. The solution here is to
make sure display_error is set to "on" in php.ini and error_reporting
to something sensible, like E_ALL & ~E_NOTICE.

E_ALL is sensible whilst developing; don't turn off E_NOTICE.

--
Andy Hassall / <an**@andyh.co. uk> / <http://www.andyh.co.uk >
<http://www.andyhsoftwa re.co.uk/space> Space: disk usage analysis tool

[Ewoud Dronkert]

On Sat, 30 Apr 2005 20:05:37 +0100, Andy Hassall wrote:

to something sensible, like E_ALL & ~E_NOTICE.

E_ALL is sensible whilst developing; don't turn off E_NOTICE.

Maybe even turn om E_STRICT (not included in E_ALL):

error_reporting = E_ALL|E_STRICT
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[johnjawed]

Zend Studio has an excellent debugger, check it out at:

www.zend.com

Xdebug is your other option, basically both "inject" themselves into
PHP and you (the programmer) can debug via their perspective clients
(which listen for their requests on specific ports on your machine,
different than MS Studio debuggers).

[Ewoud Dronkert]

On 1 May 2005 01:27:21 -0700, jo*******@gmail .com wrote:

Zend Studio has an excellent debugger [...] Xdebug is your other option

How about phpeclipse, apparently it includes a debugger (from eclipse,
or php-specific?), do you have any experience with that?
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[Chung Leong]

People should use whatever settings that's helpful. Personally I
program with E_WARNING off too.