In Objective-C, how to test against macro definition value? - objective-c

Question

I'd like to use
#define IS_APP_FULL_VERSION NO
and the code
isAppFullVersion = IS_APP_FULL_VERSION;
to set instance variable. But is there a way to also do
#if IS_APP_FULL_VERSION == "NO"
// add some methods here
#endif
but it would give a compile error, and so is #if (IS_APP_FULL_VERSION == "NO"). Is there a way to check it against YES and NO? (check against the substitution value)
Update: it seems like > and == 0 is allowed, such as
#if IS_APP_FULL_VERSION == 0
so we can actually use 0 and 1 for false and true, and use == 1 to test, but it will be better if YES and NO can be used.
Update 2:
One possible solution turns out to be:
#define IS_APP_FULL_VERSION 1
#if IS_APP_FULL_VERSION
// add some methods here
#endif
isAppFullVersion = IS_APP_FULL_VERSION;
will all work, and we can just change 1 to 0 to toggle the code.

Answer 1

Your basic problem is that the macro processor #if statement only has one data type -- integer. All #if expressions are evaluated in integer, with undefined symbols being replaced with zero. String expressions (including comparisons) cannot be evaluated.

Answer 2

Actually, normally, I would just use a flag macro rather than a value one, since there's only two cases here:
#define APP_IS_FULL_VERSION
Either define or don't define that macro. Then, if you later wanted to include/exclude code based on that, you can use:
#ifdef APP_IS_FULL_VERSION
// Do something
#endif
(or #ifndef for the opposite case, obviously).
For the code segment, it's a simple matter of using that to select the correct code:
#ifdef APP_IS_FULL_VERSION
isAppFullVersion = YES;
#else
isAppFullVersion = NO;
#endif

Answer 3

I think, you're some confused comparison MACRO.
#define format is following it.
#define MACRO_NAME VALUE (VALUE is blank spaces are also fine. MACRO_NAME need is.)
if you want comparison compile-time following like it. this is comparison mean only defined vs no defined. not YES vs NO
#define IS_APP_FULL_VERSION 1
#if defined IS_APP_FULL_VERSION
NSLog(#"full-verison");
#endif
#define IS_APP_FULL_VERSION blahblah
#if defined IS_APP_FULL_VERSION
NSLog(#"full-verison");
#endif
If you want to build separate versions of. refer a following like it.
#define IS_APP_FREE_VERSION
#if defined IS_APP_FREE_VERSION
NSLog(#"free-version");
#endif
#define IS_APP_FULL_VERSION
#if defined IS_APP_FULL_VERISON
NSLog(#"full-version");
#endif
if you want comparison runtime following like it. this is comparsion normally.
#define IS_APP_FULL_VERSION 1
if(IS_APP_FULL_VERSION)
{
NSLog(#"full-verison");
}
#define IS_APP_FULL_VERSION 0
if(!IS_APP_FULL_VERSION)
{
NSLog(#"no full-version");
}