[GRASS5] winGRASS: mingw32 and execl (g.list)

[Glynn Clements]

Markus Neteler wrote:

> > > Now a question: While 'g.list' compiled, it just does not display
> > > anything and exits. May execl() be the problem?
> > > general/manage/cmd/list.c
> > 
> 
> OK, it's not execl().
> 
> The problem is here:
> lib/gis/list.c
> 
>         if (lister)
>             sprintf(buf,"ls '%s'", path);
>         else
>             sprintf(buf,"ls -C '%s'", path);
> 
> which is unlikely to work in MS-Windows. No idea, how to
> solve that, though. Someone may implement a workaround
> for MS-Windows.

For Unix, the standard way to enumerate a directory's contents is
with opendir/readdir/closedir, e.g.:

	DIR *dir = opendir(path);

	for (;;)
	{
		struct dirent *d = readdir(dir);

		if (!d)
			break;

		puts(d->d_name);
	}

	closedir(dir);

Windows has FindFirstFile/FindNextFile/FindClose, e.g.:

	WIN32_FIND_DATA data;
	HANDLE handle;

	handle = FindFirstFile("*", &data);

	for (;;)
	{
		if (!handle)
			break;

		puts(data.cFileName);

		if (!FindNextFile(handle, &data))
			break;
	}

	FindClose(handle);

More generally, we should stop spawning external programs for simple
tasks, e.g. ls, rm, mv, cat. We need to examine all uses of system(),
G_system() and G_popen(). Many (most?) of those calls will introduce
portability issues.

-- 
Glynn Clements <glynn at gclements.plus.com>