G++ builtin for getting class name from a class object pointer?

Question

As the title asks, are they any g++ builtin function (or any method) to know the class name from a class object pointer? For instance,

class Base {
};
class A : public Base {
};
class B : public Base {
};

void some_func(Base *p) {
    printf("the name of class: %s", __some_g++_builtin_get_class_name(p) );
}

Similar to __PRETTY_FUNCTION__ in gcc builtin, I hope there would be a builtin function for g++ that help us analyze source code :)

And, clearly, what I want to print is not the Base, but A or B where it is inherited. — jaeyong, Nov 17 '12 at 05:12

score 1 · Accepted Answer · answered Nov 17 '12 at 05:20

You may be able to use typeid for this.

#include <cstdio>
#include <typeinfo>

class Base {
    virtual int foo() { return 0; }
};
class A : public Base {
};
class B : public Base {
};

void some_func(Base *p) {
    printf("the name of class: %s\n", typeid(*p).name() );
}

int main() {
    some_func(new A);
}

Unfortunately it will probably not do what you want unless your base class has at least one virtual function (otherwise the type information may not be available).

Unlike __PRETTY_FUNCTION__, the value you are looking for cannot be computed at compile time.

Thanks! it is exactly what I want. The Base class "almost always" has virtual function! — jaeyong, Nov 17 '12 at 05:35

G++ builtin for getting class name from a class object pointer?

1 Answers1