In the code I'm writing, I have been told to define a variable in a header file in the following way:
#define CLR_BLACK 0x0000
and since this is the only example I've been given, I was wondering whether all variables defined in a header file with the #define command need to be in caps. For example, would the following be valid?
#define videoBuffer (u16*)0x6000000
No. You can use any combination of alphanumeric characters and underscores. Don't start with a number.
However a variable name like videoBuffer would be difficult to distinguish from regular variables (without syntax coloring). That's why most people either use all caps for preprocessor macros or start them with a lower case k, like this: kMyPreprocessorMacro
EDIT: Those are not "global variables" by the way (as you tagged). They're preprocessor macros. Basically an automatic find and replace mechanism that is run at compile time.
No.
#define is a pre-processor macro. It replaces every occurrence of the first string after it with whatever comes after the string. The first string does not need to be in caps.
No, but it's a common and useful convention so if you're reading the code you can see what's a macro and what isn't. See C++ #ifndef for include files, why is all caps used for the header file?
