API Hooking question

[olin]

I want to hook some APIs. I has some questions when reading the article on codeguru website
http://www.codeguru.com/Cpp/W-P/dll...ticle.php/c127/

The sample in that article is to hook DirectDrawCreate function in DDRAW.dll, and change it with his own function in his own dll. I am just wondering why he set a global WH_CBT hook but with a callback function doing nothing (just do CallNextHookEx).

When I made some mouse hook or keyborad hook, I always did my work in the callback function, so I am confused that why we changed when do API hooking.

Thanks in advance!

[msg555]

That link didn't take me anywhere so I'm guessing.

He probably create a WH_CBT hook to create an instance of his dll in every process. This would be nessisary if you were trying to hook every call to an api

[olin]

Sorry about the link. it is:

<a href=http://www.codeguru.com/Cpp/W-P/dll/hooking/article.php/c127/>api hooking </a>

I think you are right. So to use WH_CBT hook is just make a chance to create the dll instance for very processes. the hook itself is not essential, and I might use some other types of global hook such as WH_GETMESSAGE hook to do the same job. Am I right? Thank you!

[msg555]

From the link

This code is intended to be included in a DLL inserted through a global Windows Hook (CBT hook for example).

looks like I guessed right