Is it possible to use a Unicode "argv"?

Question

Hi, I'm writing a little wrapper for an application that uses files as arguments.

The wrapper needs to be in Unicode, so I'm using wchar_t for the characters and strings I have. Now I find myself in a problem, I need to have the arguments of the program in a array of wchar_t's and in a wchar_t string.

Is it possible? I'm defining the main function as

int main(int argc, char *argv[])

Should I use wchar_t's for argv?

Thank you very much, I seem not to find useful info on how to use Unicode properly in C.

Answer 1

On Windows anyway, you can have a wmain() for UNICODE builds. Not portable though. I dunno if GCC or Unix/Linux platforms provide anything similar.

Answer 2

Portable code doesn't support it. Windows (for example) supports using wmain instead of main, in which case argv is passed as wide characters.

Answer 3

In general, no. It will depend on the O/S, but the C standard says that the arguments to 'main()' must be 'main(int argc, char **argv)' or equivalent, so unless char and wchar_t are the same basic type, you can't do it.

Having said that, you could get UTF-8 argument strings into the program, convert them to UTF-16 or UTF-32, and then get on with life.

On a Mac (10.5.8, Leopard), I got:

Osiris JL: echo "ï€" | odx
0x0000: C3 AF E2 82 AC 0A                                 ......
0x0006:
Osiris JL:

That's all UTF-8 encoded. (odx is a hex dump program).

See also: Why is it that UTF-8 encoding is used when interacting with a UNIX/Linux environment

Answer 4

On Windows, you can use tchar.h and _tmain, which will be turned into wmain if the _UNICODE symbol is defined at compile time, or main otherwise. TCHAR *argv[] will similarly be expanded to WCHAR * argv[] if unicode is defined, and char * argv[] if not.

If you want to have your main method work cross platform, you can define your own macros to the same effect.

TCHAR.h contains a number of convenience macros for conversion between wchar and char.