Re: C - Pass by reference to pointers

[Anitha Boyapati <anithab at sankhya dot com>]

On Fri, 24 Aug 2007, Brian Dessent wrote:

> Anitha Boyapati wrote:
> 
> >  Usually, (well I thought so) the argument expected in f() is a pointer
> >  variable. The above gives the result as 2 for the first call to f()!
> >  Why is t giving out 2 without being dereferenced in case 1 ?
> 
> You explicity cast an integer into a pointer to an integer.  The whole
> point of a cast is to tell the compiler to consider one thing as
> another.  In this case you're telling it that an integer's value is
> actually a pointer -- a completely invalid pointer, but a pointer
> nonetheless.

  Alright, you are saying that everything is interpreted as a pointer
  regardless of the value (valid or invalid). That sounds quite reasonable 
  to me. 

  I guess this sort of usage comes in handy when using pthread_create(...)
  which demands that arguments to start_routine should be of type (void *).

  Thanks.

>  There is no dereference because you didn't ask for a
> dereference.  Nothing is automatic in C, if you want the address of i
> you must write &i.
> 
> Brian
> 

-- 
Regards,
Anitha B
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