_tmain does not exist in C++. main does. _tmain is a Microsoft extension. main is, according to the C++ standard, the program's entry point. It has one of these two signatures: int main(); int main(int argc, char* argv[]); Microsoft has added a wmain which replaces the second signature with this: int wmain(int argc, wchar_t* argv[]); And then, to make it easier to switch between Unicode (UTF-16) a