I have the following error LNK2019: unresolved external symbol main referenced in function __tmainCRTStartup,
There are a lot of threads relating to this error but none of those solutions worked for me. And, none explained why this error is here.
What is your project type? If it's a "Win32 project", your entry point should be
(w)WinMain. If it's a "Win32 Console Project", then it should be
(w)main. The name
_tmain is #defined to be either
wmain depending on whether UNICODE is defined or not.
If it's a DLL, then
The project type can be seen under project properties, Linker, System, Subsystem. It would say either "Console" or "Windows".
Note that the entry point name varies depending on whether UNICODE is defined or not. In VS2008, it's defined by default.
The proper prototype for main is either
int _tmain(int argc, _TCHAR* argv)
Make sure it's one of those.
If you're getting an error on _TCHAR, place an
If you think the issue is with one of the headers, go to the properties of the file with main(), and under Preprocessor, enable generating of the preprocessed file. Then compile. You'll get a file with the same name a .i extension. Open it, and see if anything unsavory happened to the main() function. There can be rogue #defines in theory...
With UNICODE defined (which is the default), the linker expects the entry point to be wmain(), not main(). _tmain has the advantage of being UNICODE-agnostic - it translates to either main or wmain.
Some time ago, there was a reason to maintain both an ANSI build and a Unicode build. Unicode support was sorely incomplete in Windows 95/98/Me. The primary APIs were ANSI, and Unicode versions existed here and there, but not pervasively. Also, the VS debugger had trouble displaying Unicode strings. In the NT kernel OSes (that's Windows 2000/XP/Vista/7/8/10), Unicode support is primary, and ANSI functions are added on top. So ever since VS2005, the default upon project creation is Unicode. That means - wmain. They could not keep the same entry point name because the parameter types are different. _TCHAR is #defined to be either char or wchar_t. So _tmain is either main(int argc, char **argv) or wmain(int argc, wchar_t **argv).
The reason you were getting an error at
_tmain at some point was probably because you did not change the type of
If you're not planning to ever support ANSI (probably not), you can reformulate your entry point as
int wmain(int argc, wchar_t *argv)
and remove the
tchar.h include line.