How to Hook Windows API?

I am just starting out in programming, I have had one recent college coarse in C++ and have read a few books, so I know the basics and would like to try something a little more advanced. I would like to learn how to write a program that will interface with an already existing program; Such as, a program that would call up Yahoo messenger and log me in...or open the windows calculator and enter in some numbers..things like that. I assume this topic is too complex to cover here, but I can pick it up, I just need key words to enter into search engines, websites which have tutorials, recommended books and such. I just need to be pointed in the right direction. Please reply if you can help

How to Hook Windows API?
Look up spawn functions. I have used following.





strcpy(thisProgram, "OneWin.exe");


spawnl(P_WAIT, thisProgram, thisProgram, runParameters, NULL);





You can only only control other programs if they have input parameters.
Reply:I have been working with some API stuff lately myself, and I think if you enter the name of the app you want to interface with, and 'API' afterwards, you will probably find what you are looking for. You may also want to enter the letters 'SDK' after the name, as sometimes the guides to the API's for products are included in the SDK's. The 'Win32 API' is the main one to check out for Windows related stuff. For Yahoo Messenger, you might type something like


"Yahoo Messenger API SDK" into a search engine.


Good luck : )