pocc v13 warning message

[Marco]

Hi Pelle,

when I use the 'ListView_GetSubItemRect' macro, POCC displays the following warning message:

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warning #2130: Result of comparison is constant.

To reproduce the issue, please use the test files attached to this message.

The project was downloaded from the following link:
https://www.smorgasbordet.com/pellesc/zip/vlistvw.zip

I only added the following 4 instructions to the 'VListVw.c' file (everything else has been left untouched):

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#pragma comment(lib, "user32.lib")          // <-- Added
#pragma comment(lib, "comctl32.lib")        // <-- Added

...

BOOL InitListView(HWND hwndListView)
{

  ...

  RECT rc;                                                            // <-- Added
  ListView_GetSubItemRect(hwndListView, 0, 1, LVIR_LABEL, &rc);       // <-- Added - generate the warning message

}

Simply double-click the 'build.bat' file to compile the application. The batch file assumes that PellesC is installed in the default folder ('C:\Program Files\PellesC'). If not, please edit the batch file and change the value assigned to the 'PCPATH' environment variable, for example:

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set PCPATH=c:\PellesC

When building, the compiler should give some other warnings that can be ignored for the sake of this example.

Marco

[Pelle]

This is a known problem with no (good) solution.

The warning comes from how the macro is written by Microsoft:

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#define ListView_GetSubItemRect(hwnd, iItem, iSubItem, code, prc) \
  (BOOL)SNDMSG((hwnd), LVM_GETSUBITEMRECT, (WPARAM)(int)(iItem), \
    ((prc) ? ((((LPRECT)(prc))->top = (iSubItem)), (((LPRECT)(prc))->left = (code)), (LPARAM)(prc)) : (LPARAM)(LPRECT)NULL))

The condition

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((prc) ? ... : ..) is in your case

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((&rc) ? ... : ...) /* i.e. ((&rc != NULL) ? ... : ...) */ which will always be true.

There is no way to suppress a warning from a statement in a macro. To permanently disable this warning when including <windows.h> or <commctrl.h> seems unhelpful.

This could be worked around by replacing the macro with an inline function, where the warning can be suppressed, but I prefer to keep the Windows SDK as original as possible.

[Marco]

This could be worked around by replacing the macro with an inline function

Yes, this is the same solution I used.

I prefer to keep the Windows SDK as original as possible.

I agree, it is the most sensible choice.

Thanks Pelle.

Marco