HIMAGELIST_QueryInterface definition missing.
lazarus / 67-Windows

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440bx · 2025-05-28 05:51

The definition of HIMAGELIST_QueryInterface seems to be missing.

C definition is at:
https://learn.microsoft.com/en-us/windows/win32/api/commctrl/nf-
commctrl-himagelist_queryinterface

Pascal definition that must be modified to accommodate the different
definition of REFIID in FPC:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
HIMAGELIST_QueryInterface           (            { _in_  } InImageList
 : HIMAGELIST;            { _in_  } InIid        : REFIID;          {
same as PIID / PGUID  }            { _out_ } OutInterface : ppointer 
        )         : HRESULT; stdcall; external comctl32; HTH.

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marcov · 2025-05-29 10:07

Committed.

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440bx · 2025-05-29 10:11

I'm guessing you made the second parameter a "const" to cause the
compiler to pass an address.  Did I get that right ?

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marcov · 2025-05-29 11:23

Quote from: 440bx on May 29, 2025, 12:11:59 pmI'm guessing you made
the second parameter a "const" to cause the compiler to pass an
address.  Did I get that right ?

I think so. Copied it from other interface declarations. I'm wondering
about if it shouldn't be constref though in mode objfpc. That always
trips me up, as I generally use $mode delphi

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440bx · 2025-05-29 11:55

Actually, strictly speaking, neither const nor constref are correct.

The parameter is a pointer to an IID (a REFIID which is an IID by
reference) and the C definition does not _explicitly_ say that it is
constant, i.e,
Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i HRESULT
HIMAGELIST_QueryInterface(  [in]  HIMAGELIST himl,  [in]  REFIID    
riid,  [out] void       **ppv); On the hand, since it is [in] and not
[inout] then it is reasonable to presume it is constant (it is as far
as the caller is concerned.)

In that case, specifying either "const" or "constref" will produce the
same, which is passing the parameter by reference (which is what it
should do) and, the call cannot change the IID from the caller's
viewpoint since it is passed by value.

Succinctly, specifying either "const" or "constref" will yield the
same correct result.

Choosing "const" keeps that definition consistent with already
existing definitions.

One thing that would be nice would be to have an overload for the
third _out_ parameter.  That way, instead of passing the address of a
pointer, the call could pass the pointer itself (since out will take
its address automatically.)  Obviously, that's optional since C
doesn't have overloads (at least not standard C that I know of.)

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marcov · 2025-05-29 12:20

I think the difference between const and const ref is mostly in non
32-bit x86. For the rest we adhere to the style of the other calls
which is delphi inspired to avoid compatibility problems.