What's the main difference between PHP3 and 4?

[Elledan]

Can you, for example, rename all extensions of and in a php3 script to php without problems?

[Karl]

In most cases all PHP3 scripts will run in PHP4 without any modification unless some of the less common commands have being used.

PHP4 has a completly re-written parsing engine (The Zend Engine) that is much faster than the parsing engine in PHP3 and when combined with the new Optimizer it improves the speed even more.

In some cases it would be beneficial to change some PHP3 scripts as they may have custom user defined functions in them that mimick PHP4 functions now as that many new functions have been added to PHP4.

[Elledan]

Thanks for that most helpful reply, Karl!

[Karl]

No probs, I tried to find the article on PHP.net about the differences between 3 and 4 but it seems to have disappeared now, but from participation in the QA team and the mailing lists I can tell you that not many people have had problems moving scripts over.

[Elledan]

I forgot to mention that I too had searched at php.net for that particular article

Well, thanks for your help and wish me luck: I got to change a whole Bulletin board from PHP3 to PHP4... <sigh>

[Son Nguyen]

It will be no/little problem.
There are some (just a few) functions become deprecated.
Good luck

[mkaufman]

I don't believe PHP3 supports sessions, PHP4 does.

That's about the only difference that I know

[Son Nguyen]

Originally posted by mkaufman
I don't believe PHP3 supports sessions, PHP4 does.

That's about the only difference that I know

You could use PHPLIB for session management in PHP3, but it's unlike in PHP4, clear & simple!