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digitalmars.D - Static array -> Dynamic array

reply Arcane Jill <Arcane_member pathlink.com> writes:
It would appear that a function which requires a static array (for example
std.md5.sum) cannot be passed a reference

.. even though the manaul says: "When passing a static array to a function, the
result, although declared as a static array, will actually be a reference to a
static array".

In other words, if you pass in a static array, it gets converted to a reference.
But if you try to pass in a reference directly, you can't.

This is kinda curious. I had to work around this one. My workaround consisted of
declaring a static array (on the stack), passing that to std.md5.sum, and then
COPYING the result into the dynamic array where I actually wanted it (before the
function returned and the stack disappeared).

If the function expects a reference, why can't we pass one? Is there ANY WAY of
casting a dynamic array to make it look like a reference to a static array?

Arcane Jill
Jun 06 2004
parent Ilya Minkov <minkov cs.tum.edu> writes:
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I redirect this message into the newsgroup for bugs.

Problem: the function requieres a ubyte[16]. When trying to pass a 
ubyte* (technically feasible), one gets "cannot implicitly convert 
ubyte* to ubyte[16]". When trying an explicit cast, one gets "e2ir: 
cannot cast from ubyte[] to ubyte[16]" or "e2ir: cannot cast from ubyte* 
to ubyte[16]"

Test case attached.

One possible workaround would be to change the library function to 
accept a dynamic array and assert on the length of it - it should also 
make passing static arrays possible.

-eye

Arcane Jill schrieb:

 It would appear that a function which requires a static array (for example
 std.md5.sum) cannot be passed a reference
 
 .. even though the manaul says: "When passing a static array to a function, the
 result, although declared as a static array, will actually be a reference to a
 static array".
 
 In other words, if you pass in a static array, it gets converted to a
reference.
 But if you try to pass in a reference directly, you can't.
 
 This is kinda curious. I had to work around this one. My workaround consisted
of
 declaring a static array (on the stack), passing that to std.md5.sum, and then
 COPYING the result into the dynamic array where I actually wanted it (before
the
 function returned and the stack disappeared).
 
 If the function expects a reference, why can't we pass one? Is there ANY WAY of
 casting a dynamic array to make it look like a reference to a static array?
 
 Arcane Jill
 
 

Jun 07 2004