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Internet Message Format | 1996-08-05 | 1.5 KB

Path: anvil.ugrad.cs.ubc.ca!not-for-mail
From: [e-mail] (Kazimir Kylheku)
Newsgroups: comp.lang.c
Subject: Re: argc/argv & switches
Date: 6 Mar 1996 14:54:16 -0800
Organization: Computer Science, University of B.C., Vancouver, B.C., Canada
Message-ID: <[e-mail]>
References: <4h2j8j$[e-mail]> <danpop.825593142@rscernix> <[e-mail]>
NNTP-Posting-Host: anvil.ugrad.cs.ubc.ca

In article <[e-mail]>,
Jeff Rosenfeld  <[e-mail]> wrote:
>Dan Pop wrote:
>> Note that *++argv[0] is technically incorrect, because there is no
>> guarantee that argv[0] can be modified by the program, it can be legally
>> stored in a read only memory segment.
>
>Not so. The standard mandates that if main is defined with two
>parameters (which we'll call argc and argv), then:
>
>    The parameters argc and argv and the strings pointed
>    to by the argv array shall be modifiable by the program....

But argv[0] is not the argv parameter, but the first pointer pointed at by
argv. That the strings are modifiable doesn't necessarily imply that the
array of pointers through which these strings are accessed is itself
modifiable.

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''.
--