Commctrl.h notification message constants are missing

[tim-weis]

While notification message constants for standard controls (such as the edit control) are included in the generated metadata this isn't the case for notification message constants of the common controls library (defined in Commctrl.h). The following notification message constants are missing:

• ComboBoxEx
• Date and Time Picker
• Header Control
• IP Address
• List View
• Month Calendar
• Pager Control
• Property Sheet
• Rebar Control
• Status Bar
• SysLink Control
• Tab Control
• Toolbar Control
• Tooltip Control
• Trackbar Control
• Tree View
• Up-Down

Could you have a look into what's needed to get those included in the metadata?

[mikebattista]

These all use math operations that refer to other macros, which the constant scraper doesn't recognize. Probably easiest to manually define these.

[tim-weis]

Easiest, maybe, but certainly not sustainable. A cursory look through the SDK headers evidenced that those constants have changed over time, even as recent as NTDDI_WIN10_RS5 (I haven't looked into the Windows 11 SDK).

I would feel extremely uneasy about giving up the single-source-of-truth principle, just because it's easier.

[mikebattista]

We already have manual definitions where it makes sense so we wouldn't be breaking ground here.

When you say the constants have changed, I'm assuming you mean new constants were added. Otherwise, we're talking about breaking changes to APIs which usually doesn't happen especially for older API surfaces that are stable.

[mikebattista]

Are these constants supposed to be uint or int?

#define CBEN_FIRST              (0U-800U)       // combo box ex
#define CBEN_INSERTITEM          (CBEN_FIRST - 1)

Is CBEN_FIRST here -800 or is it some unchecked overflowed uint? Same question for CBEN_INSERTITEM.

[KalleOlaviNiemitalo]

The operands in 0U-800U have the U suffix, so they are unsigned, and the result is likewise unsigned.

[KalleOlaviNiemitalo]

Also, the values would be compared to the UINT code member of NMHDR.

[tim-weis]

@mikebattista Both expressions are of type unsigned int.

CBEN_FIRST evaluates to 0xFFFFFCE0, following the rules of unsigned overflow in C (which is well defined, as opposed to, say, signed integer overflow).

The expression CBEN_FIRST - 1 has operands of type unsigned int and signed int, respectively. They are of different signedness but same rank, so the second operand gets converted to unsigned int, before the arithmetic operation is performed, yielding a value of 0xFFFFFCDF with type unsigned int (refer to implicit conversions).

[mikebattista]

Thanks. I can scrape these but need to address the C# compiler warnings about overflow and checked failures. I believe unchecked should help.

[mikebattista]

See 01d36dd#diff-55fb5d5eced0797538c3656ccb571f46d8b46bddc0688f66ea459a6499e148fa.

You'll have to try them out and make sure they're the expected values. CBEN_FIRST and CBEN_INSERTITEM look correct.