Re: Concatenated if and preprocessor

Il 13/03/2025 16:44, pozz ha scritto:

Consider this code:
 if (cond1) {
...
} else if (cond2) {
...
} else if (cond3) {
...
}
 I want to activate every single if with a macro preprocessor. All the combinations are possible: only the first, only the second, only the third, the first and second... and so on.
 What's the best method to have a clean code that is always compiled without errors?

You're right, a real example is better to define my problem.
I have a project that can be compiled in different ways, depending on the final product model (it's an embedded platform, it's a material device).
I have three models with different characteristics: MODEL_A, MODEL_B, MODEL_C. Three different builds that are managed at compile time by defining MODEL macro as MODEL_A, MODEL_B or MODEL_C.
For each model, I could have a different features set. FEATURE_1, FUTURE_2, FUTURE_3, ...
#if MODEL == MODEL_A
#  define FEATURE_1   1
#  define FEATURE_2   0
#  define FEATURE_3   0
#elif MODEL == MODEL_B
#  define FEATURE_1   0
#  define FEATURE_2   1
#  define FEATURE_3   0
#elif MODEL == MODEL_C
#  define FEATURE_1   1
#  define FEATURE_2   1
#  define FEATURE_3   1
#endif
Now, on the full-featured model (MODEL_C) I could write:
if (key == 1) {
   ...
} else if (key == 2) {
   ...
} else if (key == 3) {
   ...
} else {
   ...
}
However, for MODEL_A I should have:
if (key == 1) {
   ...
} else {
   ...
}
For MODEL_B I should have:
if (key == 2) {
   ...
} else {
   ...
}
This is the scenario.
I thought using if(0) or if(1), but many times I receive some warnings from the compiler (condition is always true or condition is always false).