Olivier Langlois's blog

This is the C++ language feature that allows multiple functions to have the same name. Having multiple functions with the same name was not possible in C. The compiler is able to choose the right function by checking its parameters:

int f(int)
{
  printf("This is f(int)\n");
}

int f(char *)
{
  printf("This is f(char *)\n");
}

int test()
{
  f(1); // This is f(int)
  f("test"); // This is f(char *)
}

The way it works is that the compiler mangles function names. Mangling means that the function parameters type gets encoded in the exported function name. How a compiler mangles a function name is not specified by the standard. Hence this is one of the reasons why it is not possible to use an object file generated with compiler X with compiler Y. Most tools manipulating C++ object files (like nm) perform the reverse operation: demangling. That is extracting the function signature (including the parameters) from the exported C++ mangled function name.