https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85958
--- Comment #6 from Jonny Grant <jg at jguk dot org> --- Clang shows: $ clang -o main main.cpp -Wall -Werror -Wconversion main.cpp:15:5: error: no matching function for call to 'strstripspace' strstripspace(unused, two); ^~~~~~~~~~~~~ main.cpp:5:6: note: candidate function not viable: 1st argument ('const int') would lose const qualifier void strstripspace(int & value, int & two) ^ 1 error generated.