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Re: [leafnode-list] Compiler warnings (again)

krasel@xxxxxxxxxxxxxxxxxxxxxxxxxxxx (Cornelius Krasel) writes:

> int count( void ) {
>     struct newsgroup * g;
>     int i;
>     g = active;
>     i = 0;
>     while ( g->name ) {
> 	i++;
> 	*(g++);		/* let g point to next element of array */
>     }
>     return i;
> }
> Unfortunately, gcc barfs on the *(g++); line with "warning: value
> computed is not used".
> What am I doing wrong?

1. (not the cause for compiler warning, just standard ranting) you're
   still sticking to global variables ;) count should be passed the
   "active" which it is supposed to count, such as int count (struct
   newsgroup *active);

2. (actual problem) you calculate a dereference of that g pointer (*
   operator), but don't use it afterwards. Your compiler thus warns of
   unnecessary work.

What the compiler does with "*(g++);" is: "*g; g++;". *g is not assigned
or indexed into anywhere, the compiler says "not used".



instead of 


and it'll be fine. You can also omit all the i counter stuff and write

        return (g - active)/sizeof (struct newsgroup *);

(sizeof (void *) should be equivalent, but is less obvious); 

NB: untested

/* WHERE DOES active COME FROM? */
int count(void) {
    struct newsgroup * g=active;
    while (g->name) {
    return (g - active) / sizeof(struct newsgroup *);

Matthias Andree

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