Hi, in compl.lang.c++ I got the following answer to my problem: -------------------------------------------------------------------- On Tue, 3 Sep 2002 17:21:00 +0200, "Julia Donawald" <julia.donawald@gmx.de> wrote:

Hi, I have the following code:

[snipped code]

Calling the correct function with the entries in the map is no problem, but how can I get the return value. I tried something like that: "unsigned int i = functions["Function5"]();" but sadly it doesnt work, maybe cause in the map I declared for the return value "void"? How can I have such a map where to have functions with different return types in it and to get the return value after a call of the function through the map?

Boost has another lovely library called "any". An "any" can hold any time, with the unfortunate exception of void. Below is a partial solution to your problem that will work with any function that returns something other than void. (tested with gcc 3.2) #include <boost/bind.hpp> #include <boost/function.hpp> #include <boost/any.hpp> #include <map> #include <string> #include <iostream> class Foo { public: void Function3() const { int i =2; }; const std::string Function4() const { return "Function4"; }; unsigned int Function5() const { return 2; }; }; int main() { std::map<std::string, boost::function<boost::any> > functions; Foo foo; //functions["Function3"] = boost::bind(&Foo::Function3, &foo); //void won't work :o( functions["Function4"] = boost::bind(&Foo::Function4, &foo); functions["Function5"] = boost::bind(&Foo::Function5, &foo); // call the functions std::string s; try { //any_cast throws if you attempt a cast that isn't to the //original type s = boost::any_cast<std::string const>(functions["Function4"]()); std::cout << s << '\n'; } catch(std::exception const& ex) { std::cerr << "Wasn't a string!\n"; } std::cin.ignore(); } As a final point, there isn't really a good reason to return a cv-qualified object by value. Your const string return could be a non-const return without any break in const correctness. ---------------------------------------------------------------- Sadly it doesnt work. At this position: s = boost::any_cast<std::string const>(functions["Function4"]()); I always get an access violation..... any suggestions why? Thanks in advance Julia

I don't understand the reason for mapping boost::functions with different return type signatures ? What does it get you since to pick up the correct return value you must know exactly what each return type is for each map entry and there is nothing in the map entry itself to tell you this except the name. So you end up hard-coding knowledge of each entry in the map based on the name into your code. Doesn't sound like it gets you anything as far as design goes. Perhaps there is something wrong in your design that necessitates something like like this ? "Julia Donawald" <yg-boost-users@m.gmane.org> wrote in message news:al2tap$599$1@main.gmane.org...

Hi, I found the mistake why it throws me an exception... so now it works quite well.... what do you think about that solution in general?