Re: array of pointers

From:
Old Wolf <oldwolf@inspire.net.nz>
Newsgroups:
comp.lang.c++
Date:
29 Apr 2007 15:22:16 -0700
Message-ID:
<1177885336.216056.112350@o5g2000hsb.googlegroups.com>
On Apr 30, 4:10 am, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:

Jess wrote:

Then "x" is a const char*[3], and can decay into const char**. I've
heard about a pointer pointing to the entire array, but haven't seen
an example yet. For my example, how can I get a pointer pointing to
the whole "x" array?


    const char* (*pa)[3] = &x;

In addition, what can we use it for?


    Not sure. I can't recall ever needing one.


I use them in functions that expect to be passed a fixed-size array,
e.g.
cryptographic functions:
  bool des_cbc_checksum( byte (*out)[8], void const *in, size_t
in_len );

If so, I guess it's the responsibility of this function to check (by
some method) if the argument is a pointer or not. Is this right?


No. The responsibility lies on the caller, in most cases. Pass the
size along and treat is an an array if the size > 0. Treat it as
a single object if the size == 0.

void foo(T* p, size_t s = 0);


Wouldn't it make more sense to use 1 as the size of a single object,
and have 0 be an error?

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