constexpr

It seems to me that having a "function that always returns 5" is breaking or diluting the meaning of "calling a function". There must be a reason, or a need for this capability or it wouldn't be in C++11. Why is it there? // preprocessor. #define MEANING_OF_LIFE 42 // constants: const int MeaningOfLife = 42; // constexpr-function: constexpr int MeaningOfLife () { return 42; } It seems to me that if I wrote a function that return a literal value, and I came up to a code-review, someone would tell me, I should then, declare a constant value instead of writing return 5. Suppose it does something

I was researching what is allowed in a core constant expression* , which is covered in section 5.19 Constant expressions paragraph 2 of the draft C++ standard which says: A conditional-expression is a core constant expression unless it involves one of the following as a potentially evaluated subexpression (3.2), but subexpressions of logical AND (5.14), logical OR (5.15), and conditional (5.16) operations that are not evaluated are not considered [ Note: An overloaded operator invokes a function.—end note ]: and lists out the exclusions in the bullets that follows and includes ( emphasis mine