Does the compiler help? $ cat unsigned.cpp #include <iostream> void f(unsigned int x) { std::cout << "x = " << x << std::endl; } int main() {

Does the compiler help? $ cat unsigned.cpp #include <iostream> void f(unsigned int x) { std::cout << "x = " << x << std::endl; } int main() { f(-1); } $ g++ -Wall -Wextra -Wconversion -Werror unsigned.cpp $ ./a.out x = 4294967295 No error, no warning. The two are not really distinct types. See the link I posted above for more argumentation along these lines.