Avoiding unused variables warnings when using assert() in a Release build

Question

Sometimes a local variable is used for the sole purpose of checking it in an assert(), like so -

int Result = Func();
assert( Result == 1 );

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Answer 1

You should move the assert inside the function before the return value(s). You know that the return value is not an unreferenced local variable.

Plus it makes more sense to be inside the function anyway, because it creates a self contained unit that has its OWN pre- and post-conditions.

Chances are that if the function is returning a value, you should be doing some kind of error checking in release mode on this return value anyway. So it shouldn't be an unreferenced variable to begin with.

Edit, But in this case the post condition should be X (see comments):

I strongly disagree with this point, one should be able to determine the post condition from the input parameters and if it's a member function, any object state. If a global variable modifies the output of the function, then the function should be restructured.