illegal break

[Trafalgar Law]

I'm trying to shorten a messy and uber long tic tac toe program(not coded by me) by using functions but there's an error called illegal break

int Xwon()
{
printf("\n\t\tX won!!!\n");
				printf("\n1. New Game 0. Quit: ");
				scanf("%d", &choice);
				if (choice== 0)
				{
					printf("\nPress Enter");
					break;
				}
				else
					return main();
}

[laserlight]

You are trying to break from a function? Perhaps you want to return from the function.

What's with returning the return value of main()? It is not good practice to call main().

[cpjust]

return main();

Why on earth are you calling main()?

[Trafalgar Law]

This code wasn't coded by me.
I'm trying to shorten it by using functions on repetitive codes.

[cyberfish]

Either way you shouldn't be calling main(). It's prohibited by the standard because the implementation is allowed to add initialization calls to the beginning of main(). (Please correct me if I am wrong. I am not entirely sure about this.)

I'm sure it's not a good idea to call main(), though, as other people have pointed out.

[Trafalgar Law]

nevermind this post I'll just create my own code

[iMalc]

nevermind this post I'll just create my own code

An extremely good idea when the code you're dealing with is this broken!

[matsp]

Either way you shouldn't be calling main(). It's prohibited by the standard because the implementation is allowed to add initialization calls to the beginning of main(). (Please correct me if I am wrong. I am not entirely sure about this.)

Since this is the C forum, you are wrong. But it's still not a good thing to do, and if it's done in C++ it is indeed illegal in the standard. [main in C++ may well contain the code to construct global objects].

--
Mats

[cpjust]

Since this is the C forum, you are wrong. But it's still not a good thing to do, and if it's done in C++ it is indeed illegal in the standard. [main in C++ may well contain the code to construct global objects].

--
Mats

Why did they make that difference between C & C++ anyways?

[nonoob]

The OP was asking about an illegal break.

"break" is only permitted in code blocks from "for", "do", "while" loops, or "switch" cases. In the example above, the "break" is not within any of such blocks. The next outer level would be the function itself which is why people started to talk about breaking out of the function.

[matsp]

Why did they make that difference between C & C++ anyways?

So that main can be used to implement the "global constructor" functionality in C++. Since C doesn't have global construction, there was at the time of specifying the language, no need to prevent that. And a standards committe will not change the language standard simply because some other closely related language doesn't support the functionality that your language supports - that just means an unecessary break of backwards compatibility (even if its use is ever so ugly), whcih wins you NO friends at all.

--
Mats

[cpjust]

So that main can be used to implement the "global constructor" functionality in C++. Since C doesn't have global construction, there was at the time of specifying the language, no need to prevent that. And a standards committe will not change the language standard simply because some other closely related language doesn't support the functionality that your language supports - that just means an unecessary break of backwards compatibility (even if its use is ever so ugly), whcih wins you NO friends at all.

--
Mats

But I mean, why can't they do the global construction before calling main()?

[matsp]

But I mean, why can't they do the global construction before calling main()?

Of course, but since the compiler may not have anywhere else that it can put those things, because the compiler has no knowledge of what happens before main. It is not stated in the standard that main should do global construction, only that global construction happens some time before the user's code is called in main, and that main is not allowed to be called from the user's code. This ALLOWS the implementor to do the global construction inside main, but it is perfectly valid to do that somewhere else too.

gcc DOES implement main as the place to call global constructors, but I beleive MS VC++ doesn't.

--
Mats

[cpjust]

Of course, but since the compiler may not have anywhere else that it can put those things, because the compiler has no knowledge of what happens before main.

If the compiler doesn't setup what happens before main() then who does?
I thought the compiler creates everything from the point when the OS starts the program?

[master5001]

Don't pick on semantics, cpjust. The compiler does not know anything. It does precisely what you tell it to do. And if you start assuming it is just going to know what you mean without being very explicit, you will probably find you just wrote a program that triggers some compiler warnings... Or your linker will not be too thrilled with your compiler's output. If you ever write a program in assembly language you will find there is no magic to beginning a program. There are no glorious steps that one needs to take prior to executing a function called "main." Your compiler doesn't work miracles, then call your main implementation. It just writes out the machine code required to execute your main fuction.

And VC++ does do global initialization slightly differently than GCC, for the record. Microsoft initializes things prior to calling main.