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| Date: | -- (:) |
| From: | Jed Davis <jdev@p...> |
| Subject: | [Caml-list] Re: void/unit in C calls |
"Lars Nilsson" <lazarus13@hotmail.com> writes:
> Does this indicate an error in the O'Caml manual, section 18.5.1, where
>
> void foo(value v1, value v2, value v3)
> {
> CAMLparam3(v1, v2, v3);
>
> CAMLreturn0;
> }
>
> is used, in addition to a paragraph preceeding it in the same section
> saying "If your C function is a procedure you must insert CAMLreturn0
> at the end"? In fact, CAMLreturn0 existing at all seems to imply the
> fact that unit-returning functions (from O'Caml's point of view) can
> be void in the C implementation.
It doesn't say that foo() is meant to be the implementation of an
external in and of itself; in fact, the absence of a CAMLprim
indicates that it's not meant to be one. It's just that any function
that might set off a GC needs to declare its "value"s so they can be
updated if the referenced blocks are moved, and thus needs a matching
CAMLreturn.
--
[Jed Davis] A098 903E 9B9A DEF4 168F AA09 BF07 807E F336 59F9
<jdev@panix.com> 0xF33659F9
"But life wasn't yes-no, on-off. Life was shades of gray, and rainbows
not in the order of the spectrum." -- L. E. Modesitt, Jr., _Adiamante_