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algorithm_signed() and algorithm_unsigned() in the conditional compilation example need to be templated functions for the example to make (more) sense.

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Is algorithm being templated not enough?

Two points. 1) Currently, the code could be written with normal overloading (one for int and one for unsigned). No traits required. 2) The current code relies on an implicit cast to int or unsigned int. I’m not sure that’s good.

> Currently, the code could be written with normal overloading (one for int and one for unsigned). No traits required

f( (uint8_t)0 ) will dispatch to the overload f(int) with overloads. The type-trait code will dispatch to f_unsigned(unsigned).

I didn't believe you but you're right. The uint8_t gets promoted to int, not unsigned int.

https://godbolt.org/z/icQHw3

C’s integer promotion rules aren’t the best.

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