Hi Thomas, thanks again for your "lecture in c thinking", this is very helpful for someone who made her way into programming, and IT in general, starting with Java 5 and Racket (pardon me, it used to be called scheme then :-; ) :-)
>> > > Correct, the caller has to provide a storage location for the output > she's interested in and may pass NULL to indicate that no storage has > been allocated because she's not interested in a return value. That's good to know, I really was not aware of such a convention - but it makes sense as soon as you think about pointers as "storage allocation"! In fact I remember I've already told myself before to always think of "storage allocation" when I read "pointer", but when you're not exposed to something for a long time you just forget things ... > > In C++ output parameters are often declared using reference types, which > are a special kind of pointer types that is always implicitly > dereferenced when used in expressions and cannot be set to NULL Yes, I think the C++ references were closer somehow to what I assumed (closer in "meaning"/intent I mean, not technically). (Not that I've worked with C++ too much either, just some very cursory exposure... :-;) Thanks again, Sigrid > explicitly (at least not if the expression used to do so is simple > enough for the compiler to realize what you're up to ;-) > > If you declare a (_ptr o _something) type, racket always allocates space > for a something, passes the pointer to the foreign function and then > dereferences it to extract the _something after the foreign function > returns. Racket should indeed never pass a NULL pointer here. > > Ciao, > Thomas > > > -- > When C++ is your hammer, every problem looks like your thumb.
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