Can Static-libraries functions get inlined?

lets say I have these files

main.cpp

#include <lib/header.hpp>
int main() {
    return lib::meaningoflife();
}

lib/header.hpp


namespace lib {
    int meaningoflife();
}

lib/source.cpp

namespace lib {
    int meaningoflife(){ return 42;}
}

Will main just return 42 directly or will it have to call the function? If I make lib a ststic library and link it to my program or does it still require LTO?