Question

I want to get the type name and print it for debug purposes. I use the following code:

#include <cxxabi.h>

inline const char* demangle(const char *s) {
    abi::__cxa_demangle(s, 0, 0, NULL);
}

template<typename T>
inline const char* type_name() {
    return demangle(typeid(T).name());
}

It works well, but it I suppose there is an unnecessary runtime overhead. Is there any way to get a human-readable form of type ids that is computed at compile time? I am thinking of something that looks like this:

boost::mpl::type_name<MyType>::value

Which would return a string constant of the type name.

Answer 1

I can’t see typeid(T).name() incurring a runtime overhead. typeid(expr) yes, if expr is of a polymorphic type.

It looks like the demangling probably happens at runtime, but there’s not an awful lot you can do about that. If this is only for debugging then I really wouldn’t worry about it too much unless your profiler indicates that this is causing your program to slow down so much that debugging other elements of it is troublesome.