Re: A function returning string or pointer

svata wrote:

Hello to all,

as a result from my previous post I'm busy with splitting code into
functions.
The one problem ( out of many ) I encounter is how to properly
use/code a function which returns either array of characters(string) or
a pointer to this array.

You /must not/ return a pointer to an array which is a local
non-static variable of the function.

I read some articles, some other posts and come to this solution:

char *read_name(void){
static char item_name[11];

(fx:snip)

return item_name; /* return string in the form of character array */
}

So you /must not/ do this. The variable `item_name` evaporates when
the function returns, so the pointer to it isn't pointing anywhere
and any use of it gets you undefined behaviour -- which is a Very
Bad Thing.

You must return a pointer to store which will outlive the function
call: for example:

* a static array, usually a bad idea because different uses of the
function will share that array.

* mallocated store (which the using code will have to free)

* store passed in as an argument (so it's the caller's problem)

* mix as desired (carefully)

--
Chris "hantwig efferko VOOM!" Dollin
Meaning precedes definition.

.

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