There's any way to check the size of a define?

[E_Blue]

I have a header file that have some default values and I want to avoid the compilation if one of them is too big in length.

I tried the following code without success

[Ttelmah]

A define, does not exist.
It has no size, till you put it into a variable. The variable then has a size.

#DEFINES in C, are text macro substitutions, not variables.

All the #functions are carried out by the pre-processor, before any 'C' even exists. sizeof, is a C function, which hasn't even been loaded yet...

[temtronic]

hmm... rainy day here..
I tired this..
...
#define BUFFER_SIZE 17
#if BUFFER_SIZE>16
#error Buffer size is too large
#endif
...

does work, well it compiles and if BUFFER_SIZE is <17 no msg appears.
when it's >16 the error msg appears

if you change
#define DefaultCode "7777"
to
#define DefaultCode 7777

then
#if DefaultCode >7777
#error Check config file
#endif

maybe it'll work ??

If you want to check for DefaultCode being more than 4 space wide, then test for >9999.

like I said rainy day here..slipping on water on ice is NOT fun.

Jay

[Ttelmah]

Yes. The preprocessor supports arithmetic tests. But that is all.
You can test a numeric value, or it the define itself exists.
No 'strings' or sizes.

So if you made your value a numeric value as opposed to a string, you could refuse it if it was >9999. However it couldn't then contain text like "ABCD".

[E_Blue]

Thanks for your answers.
So I can apply this only to numeric values but not strings.

I guess i will must have care about those strings one by one by my self.
_________________
Electric Blue

[Ttelmah]

In C itself, once you put the define into a variable, you can of course check this.