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int XXX WinMain

For Beginners

Started by mashrub May 30, 2006 01:01 PM

9 comments, last by yadango 17 years, 11 months ago

mashrub

122

Author

May 30, 2006 01:01 PM

int WINAPI WinMain // ...
int PASCAL WinMain // ...

Hello, I'd like to know what do the "WINAPI" and "PASCAL" things mean and what purpose they serve. Are there any other like these? Thanks for your replies!

Fruny

1,658

May 30, 2006 01:03 PM

They are macros that (should) evaluate to something like __declspec(stdcall), specifying the calling convention that is standard to the Windows API.

See here for more.

edit: linked to MSDN rather than Wikipedia.

"Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." — Brian W. Kernighan

mashrub

122

Author

May 30, 2006 01:18 PM

Hey, thanks for that!
Now, I'd like to know something else: is it compulsory to tell the compiler the calling convention of the WinMain function?

JBourrie

1,204

May 30, 2006 01:40 PM

I "think" (and by think I mean am possibly talking out of the left edge of my ass) that it is there to tell certain Non-VS compilers what the convention is. In Visual Studio, it can be left out without any (that I know of) effect whatsoever.

Check out my new game Smash and Dash at:

http://www.smashanddashgame.com/

Agony

3,452

May 30, 2006 01:44 PM

In the project settings, you can set the default calling convention. I believe the default is cdecl, so if you need stdcall or something else, you'll either have to manually specify the alternate calling convention wherever you need it, or you will have to change the project-wide calling convention and use that everywhere (or manually specify cdecl when you want it).

"We should have a great fewer disputes in the world if words were taken for what they are, the signs of our ideas only, and not for things themselves." - John Locke

Colin Jeanne

1,115

May 30, 2006 07:27 PM

Generally it's best to leave your project settings alone and just specify WINAPI before things like WinMain() and your window procedures.

Anonymous

May 30, 2006 10:29 PM

I don't know if including the calling convention is necessary (it may well be depending on your compiler), but I believe including it explicitly the declaration is just good form.

Colin Jeanne

1,115

May 30, 2006 11:32 PM

It is for MSVC++ (I know because I forgot to write WINAPI when defining WinMain() today [smile])

Emmanuel Deloget

1,382

May 31, 2006 04:08 AM

Quote:Original post by JBourrie
I "think" (and by think I mean am possibly talking out of the left edge of my ass) that it is there to tell certain Non-VS compilers what the convention is. In Visual Studio, it can be left out without any (that I know of) effect whatsoever.

Not completely true. If you don't tell the calling convention, the compiler assume that you use the c calling convention - which is different from the stdcall one. Most WinAPI callbacks are supposed to be stdcall - if you feed a function with a callback that is not stdcall, you'll probably going to screw your stack and to crash.

Regards,

-- Emmanuel D. [blog, in French] [blog, very bad googlized translation]

mashrub

122

Author

May 31, 2006 11:03 AM

OK then, so I'd better just specify it for better compatibility ;)
Thanks!