About The main() Function

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Every C and C++ program must have a program-startup function:

• Console-based programs call the main function at startup and the wmain function for UNICODE programs.
• Windows GUI programs call the WinMain function at startup and the wWinMain function for UNICODE programs.

Where you place the startup function is a matter of preference. Some programmers place main at the beginning of the file, others at the end. Regardless of its location, the following points about main always apply:

• _TCHAR Mapping (for UnicodeString, _tMain and _tWinMain)
• Arguments to main()
• Wildcard arguments
• Using -p (Pascal Calling Conventions)
• The value that main() returns

Our Clang-enhanced C++ Compilers (BCC64, BCCIOSARM, and BCCAARM) now enforce the requirement that declarations have a type in C++. So, for example, you now receive an error if WinMain has no return type, as in:

WINAPI _tWinMain(HINSTANCE, HINSTANCE, LPTSTR, int)
{
  ...
}

The above now generates the following error:

C++ requires a type specifier for all declarations

To remedy this error, update the code to read:

int WINAPI _tWinMain(HINSTANCE, HINSTANCE, LPTSTR, int)
{
  ...
}