Re: Debuggin PHP

On Wed, 2006-04-26 at 14:51, Sameer N Ingole wrote: > Robert Cummings wrote: > > On Wed, 2006-04-26 at 12:44, Jochem Maas wrote: > > > >> hicham wrote: > >> > >> easy way 2: > >> use lots of echo()/var_dump()/print_r() in your code to figure out > >> where it's breaking. > >> > > > > If you're trying to track down an error using this technique (by far one > > of the most popular techniques and time tested), be sure and use your > > knowledge of binary search algorithms to speed up your search. Applying > > the heuristic of guessing approximately where it's occurring will help > > you greatly also :) This kind of technique though is mostly only > > necessary when PHP does something stupid like segfault *grin*. > Most of the times it is true, however, sometimes everything just fails. > Apache continues to give segfaults on running a specific PHP script, > which do don't find until you look into error logs of apache. Then you > try to generate backtrace using gdb. All this while, on every try > Apache+PHP keeps crashing on you. > > gdb backtrace too does not help much. So finally you compile bare bones > apache+php and Voila! Everything works just fine.. From there, you go on > adding one module per compilation to find the defaulter module and run > /that/ PHP script after every compile to see if it crashes. And after a > few compiles you find an Apache module to be a real culprit. I use binary search for module seg faults also when the module is unknown :) Also for segfaults, the error log (or just plain run from CGI) can be handy to see your output before the crash. Cheers, Rob. -- .------------------------------------------------------------. | InterJinn Application Framework - http://www.interjinn.com | :------------------------------------------------------------: | An application and templating framework for PHP. Boasting | | a powerful, scalable system for accessing system services | | such as forms, properties, sessions, and caches. InterJinn | | also provides an extremely flexible architecture for | | creating re-usable components quickly and easily. | `------------------------------------------------------------'