From: William Djaja Tjokroaminata <billtj@...>
Date: 2002-10-25T06:23:41+09:00
Subject: Re: rb_gc_register_address problem

Hi Paul,

Paul Brannan <pbrannan@atdesk.com> wrote:
> I can't use a vector of strings (*), because I need to pass this data to
> function that someone else wrote with a signature that looks like:
>   void foo(int & argc, char ** argv);

I guess then it is that person who mixes C++ with C.  It is not even

    void foo (int argc, ...)

nor

    void foo (const int & argc, ...)

So the signature may indicate that he intends to modify argc, in contrary
to common C functions of similar type (such as also shown in Ruby source
codes).

> I can easily pass a vector<char*> to foo() with:
>   std::vector<char *> args;
>   ...
>   int argc = args.size();
>   foo(argc, &args[0]);

This whole function argument passing is rather frightening because, first
as pointed above, the person may modify argc, and second, then he may also
modify argv, in which case then the original vector may be broken.  Unless
I can read the whole content of foo, I personally will not be comfortable
of using foo using this scheme.

> The performance constraints the C++ standard puts on a vector almost
> 100% guarantees this to work portably.

Because of the O(1) requirement, do you know of any instance where the
vector is implemented differently (using a deque, perhaps)?  I do not know
too many STL libraries.

Regards,

Bill