Can we overload main() function in C++? [duplicate]

Question

Since C+++ allows function overloading, can we overload main()?

For example,

int main(const std::string &)
{
   return 0;
}
int main(int argc, char *argv[])
{
  return main("calling overloaded main");
}

gcc-4.3.4 doesn't compile this, and gives these errors: (see at ideone)

prog.cpp:4: error: first argument of ‘int main(const std::string&)’ should be ‘int’
prog.cpp:4: error: ‘int main(const std::string&)’ takes only zero or two arguments
prog.cpp: In function ‘int main(int, char**)’:
prog.cpp:8: error: declaration of C function ‘int main(int, char**)’ conflicts with
prog.cpp:4: error: previous declaration ‘int main(const std::string&)’ here
prog.cpp: In function ‘int main(int, char**)’:
prog.cpp:10: error: invalid conversion from ‘const char*’ to ‘int’
prog.cpp:8: error: too few arguments to function ‘int main(int, char**)’
prog.cpp:10: error: at this point in file

So I'm wondering if the C++ Standard explicitly forbids overloading of main? If so, which statement?

Answer 1

Yes it explicitly forbids that. Refer to 3.6.1p2

An implementation shall not predefine the main function. This function shall not be overloaded.

---

This way, the main function's name can stay unmangled. That is, the runtime library can call a symbol having a fixed name (e.g main or _main) to jump to the main function. The libraries' code will not need to depend on what parameter list the program's main function has.

The implementation is also allowed to define additional valid parameter lists for the main function (The POSIX spec specifies a char **env parameter for the environment variables, for example). It would not be clear when an overload of main is a "non-main function" or whether it's a "main function", thus an entry point. Presumably, you would want to get an error if you would declare more than one entry point, so such issues are important.