Thread: Compiling issue with the OpenGL tutorial by RoD

Originally Posted by Ken Fitlike

So you no doubt fully appreciate how ultimately futile this is as an approach to learning.

Fully. Like I said I simply was lazy and wanted to see what the program accomplished before reading about exactly what each part does. I'll try and decipher your message and then go from there. Thanks.

Edit: I'm sorry, but I didn't understand the vast majority of that second paragraph. I've done the basic tutorials and understood as much as my mind would allow, but I'm still lost. Maybe I should look into a book or something.

Originally Posted by Twitchmokey

Edit: I'm sorry, but I didn't understand the vast majority of that second paragraph. I've done the basic tutorials and understood as much as my mind would allow, but I'm still lost. Maybe I should look into a book or something.

The warnings are telling you that the compiler expects a numeric type as parameters but are being given NULL, which it regards as a pointer type. For the first warning, CreateWindowEx expects a DWORD as the first parameter ie it should be a number and NULL isn't intended to be used as a number but as a pointer value; it's either defined as (void*) 0 or 0 (zero) depending on whether you're compiling c or c++ but its use implies a pointer. The warning tells you that NULL is a pointer and not a number; it's asking you why you are trying to bash a square peg into a round hole(even though it will convert NULL to zero if you choose to ignore the warning, which you shouldn't).

Likewise, the 3rd and 4th parameters of PeekMessage are numerical types, too, and NULL should never be used where a numeric type is intended or expected, so change them to zero, too.

Originally Posted by Desolation

NULL is defined as 0.

Originally Posted by windef.h

#ifndef NULL
#ifdef __cplusplus
#define NULL 0
#else
#define NULL ((void *)0)
#endif
#endif