Re: [Gluster-devel] Can function arguments be modified ?

[Xavier Hernandez]

On 10.03.2012 21:34, Anand Avati wrote:

> There is a no rule written on stone here. It is good practice to make
> copies. Note that for things like iatt structure, you need not
> "allocate" and "free" from the heap. Most of the time you can copy to
> a structure on the stack, modify and return that. You will see that
> for parameters which get modified in the callback (typically
> aggregated from multiple subvolumes), most translators have a
> "modified" copy inside frame->local.
>
> Avati
Basically my problem was with dict_t. I already make copies of iatt and other simple structures without explicit memory allocation. These are cheap but anyway, if that were unnecessary, better not doing needless work.
 
So, in general I can assume that all translators will make a copy if they modify any argument I pass to them, and I can use a COW (copy on write) policy for all structures I receive, either regular or callback calls. Right ?
 
I had already seen that some translators were making copies, but I hadn't found any "official" statement saying that this was the way to do it. I just wanted to be sure.
 
Thank you very much
 
Xavi