NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c-part1/8968

Text File | 1996-08-05 | 1.7 KB | 49 lines

Path: mail2news.demon.co.uk!genesis.demon.co.uk
From: Lawrence Kirby <[e-mail]>
Newsgroups: comp.lang.c
Subject: Re: argc/argv & switches
Date: Thu, 07 Mar 96 17:36:39 GMT
Organization: none
Message-ID: <[e-mail]>
References: <4h2j8j$[e-mail]> <danpop.825593142@rscernix> <[e-mail]> <[e-mail]>
Reply-To: [e-mail]
X-NNTP-Posting-Host: genesis.demon.co.uk
X-Newsreader: Demon Internet Simple News v1.27
X-Mail2News-Path: genesis.demon.co.uk

In article <[e-mail]>
           [e-mail] "Kazimir Kylheku" writes:

>However, if it were the case that these pointers are not modifiable, would not
>the declaration of main() be required to be written as:
>
>int main(int argc, char * const *argv)
>
>        or
>
>int main(int argc, char * const argv[])
>
>That is, ``argv is a pointer to a vector of constant pointers to modifiable
>chars''.

This is not required any more than the type of a string literal is required
to be const char [x]. You can refer to a const object through a non-const
lvalue however if you try to modify the object you get undefined
behaviour. The const was probably left out to maintain backwards compatibilty
with existing code. Such code could easily contain lines such as:

   char **ptr = argv;

which would break with a const declaration of argv. Of course the standard
declaration breaks if I try to use:

   char *const *ptr = argv;

which is a pity but not disasterous!

--
-----------------------------------------
Lawrence Kirby | [e-mail]
Wilts, England | [e-mail]
-----------------------------------------