RE: [Sablevm-developer] Re: Config File Parsing

[Brent F. <bre...@xp...>]

I've got a stupid C question:

Is it possible to modify the char* vector "argv" passed from
the command line?

Based on our earlier e-mail, I would anticipate the following:

1.  User starts sablevm with one or two command line options.
2.  SableVM opens and parses the /etc/sablevm file.  (This works)
3.  SableVM must then insert options from the /etc/sablevm file
    into the argv that gets passed to the "popt" library for
    parsing.

How does this work?  I tried a realloc on the argv vector, but
that caused a segfault.

In fact, more generally, how do you do something like this:

int main()
{
	char* args[3] = { "--foo", "--bar", "--baz" };
	int argc = 3;

	do_something(&argc, args);
}

void do_something(int* argc, char** argv)
{
	/* Add some new fields */
	char* data = realloc(*args, 1000);
	/* I think this actually just macs args[0] = a buffer of
	   size 1000.  It doesn't grow the whole block. */

	data[4] = "--more_stuff";
	/* I think this 
	...
}

The problem I'm having is with conceptualizing pointer-to-pointer
versus array-of-pointers.  How can I achieve the desired behavior
of basically "growing" an array of pointers?

I know how I would achieve this under C++, but I'm unclear as to
the proper behavior under C.

Any help *greatly* appreciated.

Thanks,

-Brent