why cannot assign to function call
mdw at distorted.org.uk
Fri Jan 9 14:47:43 CET 2009
rurpy at yahoo.com <rurpy at yahoo.com> wrote:
> As a side comment (because it always bugs me when I read this, even
> though I read it in very authoritative sources), ISTM that C passes
> everything by value except arrays; they are passed by reference (by
> passing a pointer to the array by value.) Admittedly, the close
> relationship between arrays and pointers makes it easy conflate them.
Arrays are distinctly second-class citizens in C.
Basically, in C, arrays aren't passed at all but there's some syntactic
sugar so you can squint and con yourself that they're passed by
If you try to pass an array, the array name immediately decays to a
pointer, and the pointer gets passed instead -- by value. The
corresponding function parameter must be a pointer to an approrpriate
kind of thing, though you're allowed to write s to confuse yourself if
you like -- T D in a function parameter declaration means precisely
the same as T *D -- to the extent that &D has type T **D and so on.
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