🚀 go-pugleaf

"Eugene Radchenko" <eugene@qsar.chem.msu.su> writes:

>I have just realized that something is grossly overlooked in C++ standard.

I think the problem is due to Microsoft overlooking the C and C++
standards, not vice versa.

>It requires every program to have the main() function (which implementation
>is not allowed to supply) with parameters (void) or (int argc, int*argv[]).

The implementation is allowed to make the program work even if main() is
not defined, so long as it issues a diagnostic.

>However, Windows programs have another convention: prrogram must contain
>the function
>  int WinMain(HINSTANCE curInst, HINSTANCE prevInst, LPSTR cmdline, int cmdShow)

A compiler is allowed to accept the program

	int WinMain(HINSTANCE curInst, HINSTANCE prevInst, LPSTR cmdline,
		int cmdShow)
	{
		return 0;
	}

so long as it issues at least one diagnostic, e.g.
"warning: standard C++ requires a definition of main()".

But if a compiler does not accept

	int main() { return 0; }

as a complete program, then that compiler is not a conforming C or C++
implementation.

>Some of this is of course quirks or even outright ignored in Win32
>(prevInst), but the full non-parsed command line could be useful sometimes,
>and not all implementations provide the function retrieving it.

In many operating systems, the command-line parsing is done by the
shell, not the OS.  Such operating systems cannot provide the non-parsed
command line.

>And anyway this is definitely not a main() from the specs.
>Maybe the requirements on the main() should be relaxed somehow?

Are you suggesting relaxing the requirements on implementations,
or the requirements on programs?

I presume you are referring to 3.6.1[basic.start.main]/1:

|	A program shall contain a global function called main, which is the
|	designated start of the program.

You are correct to infer that this means that all Windows programs
which do not define main() are ill-formed.

However, that means only that a compiler is required to issue
a diagnostic; it does not mean that the compiler must reject the
program.

Obviously a program that does not define main() is not going to be
portable, so I don't think that requirement on programs should be
relaxed.

Windows compilers which wish to conform to the C and C++ standards
should include code similar to

	HINSTANCE __curInst;
	HINSTANCE __prevInst;
	LPSTR __cmdline;
	int WinMain(HINSTANCE curInst, HINSTANCE prevInst, LPSTR cmdline,
		int cmdShow)
	{
		int argc;
		char **argv;

		__curInst = curInst;
		__prevInst = prevInst;
		__cmdLind = cmdLine;
		__parse_command_line(cmdline, &argc, &argv);
		return main(argc, argv);
	}

in their libraries, so that they can accept programs which define main()
but not WinMain().

--
Fergus Henderson             	WWW: http://www.cs.mu.oz.au/~fjh
fjh@cs.mu.oz.au              	PGP: finger fjh@128.250.37.3
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