> int essid_alloc(
>     size_t length,
>     char ** result
> ) {
>     char * tmp;

>     if(length==0 || !result)
>         return EINVAL;

>     tmp = (char *) calloc(length, 1);

>     if(!tmp)
>         return ENOMEM;

>     *result = tmp;

>     return 0;
> }