Re: Access to array slices?

["David Thompson" <david.thompson1@worldnet.att.net>]

sk <sk@noname.com> wrote :
...
> An example of why I ask,
>
> int readlink(const char *path, char *buf, size_t bufsiz);
>
>      Path => ICS.Chars_Ptr
>
> however
>
>      Buf => access IC.Char_Array
>
> The choice seems dependent upon whether the imported
> function allocates or expects the caller to allocate.
>
Allocation has nothing to do with it; a C routine cannot
allocate unless it *returns* a pointer or receives a pointer
*to* a pointer (or receives a pointer to or returns a struct
*containing* a pointer, but that's much rarer).

The choice probably should be and at least here apparently is
dependent on whether the C code expects/requires a char pointer
to point to a C string, which is one or more char elements the last
of which and only the last is a null (terminator); or to "just" chars,
one or more, which can contain arbitrary data including nulls.

(readlink actually *could* have been designed and specified
to treat the target as a C string, since in practice it never
contains a null and its maximum size can be bounded,
but it wasn't, probably for consistency with other routines
like read and recv which cannot.)

--
- David.Thompson 1 now at worldnet.att.net