First C program

Hi Jevgeni

WOW, many thanks. I have updated the program.

Proves I still dont understand pointers, especially when to use a pointer
to pointer.

I definitely did not want to use global. It was all I could get to work.



I did some more learning and I found this, here
http://www.eskimo.com/~scs/cclass/int/sx8.html

'What are pointers to pointers good for, in practice? One
use is returning pointers from functions,

'via pointer arguments rather than as the formal return
value.



So the answer to my confusion is , when you want to return a pointer in a
function arg,

you need a pointer to a pointer.



Frank

*Subject: Re: First C program

*From: Jevgeni Astanovski <Jevgeni.Astanovski@xxxxxxxxxxxxx>

*Date: Thu, 3 Apr 2014 11:17:52 +0000

If you want to open a file in a function and have its pointer available in

main, you must pass pointer to pointer!

Something like this:

int main()

{

_RFILE *fp ;

openfile(&fp) ;

}

void openfile(_RFILE **fp)

{

*fp = _Ropen(...) ;

}

(Bad) Alternative is to have it defined as global variable.