I'm just about to run it through debugger again right now ... I'll take a look whether the character sets aren't different. Right now (e.g. when I ran it through debugger for the last time) I discovered it is directly related to OpenGL extensions, or GL context creation (or it seems to be related to them).
Okay, got more info ...:
I wonder why I get NULL pointer when getting OpenGL extensions list through standard way glGetString(GL_EXTENSIONS); so right now I know where the first issue is (hope there isn't any second). Huh... so it actually isn't problem in strstr, but more like that I don't have the list to perform compare.
Anyway I still don't get why glGetString(GL_EXTENSIONS); returns NULL pointer... huh. Could it be wrong glext, or issue while creating OpenGL context?
And even more info ...:
Creating windows OpenGL window as specified on MSDN. The funny thing is, I actually get Device context = -620687535 (could be good adress, but I think it should be positive, not?), but rendering context is probably invalid (65536 - or is it valid?). Any more info on this?
I finally managed to run the application and it "works" (that Device context and Rendering context was alright ... ). Reed, you were right it was due to different character sets (Not in the strstr, but during window creation). Thanks. I seriously need to get some more Windows and WinApi programming again, after so long time in Linux.