Valhalla Legends Archive

I've seen main functions with arguments before. ie:


int main(int something, int something_else)


What's passed to the main function? Is that for like.. variables passed via command line or something?

Standard main is:
int main(int argc, char *argv[])

argc is the number of commandline arguments, and argv is an array of the arguments,

• being the name of the program.

Cool, thanks!

Quote from: iago on March 27, 2003, 07:43 PM
Standard main is:
int main(int argc, char *argv[])

argc is the number of commandline arguments, and argv is an array of the arguments,

• being the name of the program.
  

Don't forget:
int main(int argc, char *argv[], char *envp[])

I've not seen that one...what's the third param for? What would a second array of strings do there?

I would guess they are environmental variables, seeing as though it's called envp

Yes.

All three forms (0, 2, 3 parameters) are acceptable.

Quote from: Yoni on March 29, 2003, 04:33 AM
Yes.

All three forms (0, 2, 3 parameters) are acceptable.

void main() is not acceptable, however, despite what Visual C++ might try to tell you.

envp is Windows specific, iirc.  Use getenv() instead.

Quote from: Kp on March 29, 2003, 06:23 PM
envp is Windows specific, iirc.  Use getenv() instead.

Ah, you're right.  According to documentation, I've found, it's something most Windows and UNIX compilers implement, but not a standard feature.

int main(int argc, wchar_t *argv[]);
is this not supported?

Quote from: Etheran on April 08, 2003, 04:01 AM

Code Select Expand

int main(int argc, wchar_t *argv[]);
is this not supported?

If you want the argv argument to be a wide string, you'll have to rename main to wmain.

MSVC++ also allows the following:
int _tmain(int argc, TCHAR* argv[]);

Similarly with WinMain:
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR lpCmdLine, int nShow);
// or
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, LPWSTR lpCmdLine, int nShow);
// or
int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE, LPTSTR lpCmdLine, int nShow);

I've also seen void main(void) {...} (This is with C btw) is that legal? And add preformated text tags, i dont like how [ code][/code ] creates a new line....

Quote from: MrRaza on April 08, 2003, 07:00 PM
I've also seen

Code Select Expand

void main(void) {...} (This is with C btw) is that legal? And add preformated text tags, i dont like how [ code][/code ] creates a new line....

No, that's not standard C (or C++). http://www.eskimo.com/~scs/readings/voidmain.960823.html
void main is simply wrong.

Well, i guess my C++ book is wrong, but hey atleast it has some good AI information in it..