Re: [xml] what should to be 'const'?

[massimo morara <m morara 3di it>]

On Mon, May 21, 2007 at 10:00:03AM -0700, Rush Manbert wrote:
> massimo morara wrote:
> >     In the function xmlCopyNode(const xmlNodePtr node, int 
> > extended) [tree.c], what is supposed be 'const'?

> Write the declaration out, then read it backwards to determine what is 
> const. In this case, I believe the declaration would be "const xmlNode 
> *", so reading it backward says that it's a pointer to a xmlNode that is 
> const. A const pointer would be "xmlNodePtr const node"

        Sorry, but i'm pretty sure that "const xmlNodePtr node" is (in
"tree.h") "xmlNode * const node", so is the pointer that is costant;
next i transcribe a little trivial program to verify a similar case.
        My question is: what we wish costant: the pointer or the data?
        If we wish that is costant the structure pointed, we should
write "xmlNode const * node" or, defining in "tree.h" something like

typedef  xmlNode const *  xmlConstNodePtr;

write "xmlConstNodePtr node".
        For xmlCopyNode() and for other functions.

                massimo morara


ps: sorry for my bad english


---- test program ---- 


#include <stdio.h>

typedef struct
 {
   int foo;
 } fooStruct ;


typedef  fooStruct *  fooStrPtr;


void  changeFooData (const fooStrPtr  pfd)
 {
   pfd->foo = 2;

   /* pfd++; forbidden */
 }


int main (void)
 {
   fooStruct  fooData;

   fooData.foo = 1;

   changeFooData(&fooData);

   printf("foo val: %i\n", fooData.foo);

   return(0);
 }