DEVMODE structure has fields with incorrect types

[Skrity]

Which crate is this about?

windows

Crate version

0.42.0

Summary

When querying display via EnumDisplaySettings(A,W,ExA,ExW) display parameters get inserted into wrong fields. Tested on 2 pcs so far.

Toolchain version/configuration

Default host: x86_64-pc-windows-gnu
rustup home: C:_scoop\persist\rustup.rustup

stable-x86_64-pc-windows-gnu (default)
rustc 1.64.0 (a55dd71d5 2022-09-19)

Reproducible example

fn main() {
    use windows::Win32::Graphics::Gdi::*;
    let mut dm = DEVMODEA::default();
    dm.dmSize = std::mem::size_of_val(&dm) as u16;
    let b = unsafe {EnumDisplaySettingsExA(windows::core::PCSTR::null(), ENUM_CURRENT_SETTINGS, &mut dm, 0u32) };
    println!("Result: {:?}",b);
    println!("dmBitsPerPel: {:?}", dm.dmBitsPerPel);
    println!("dmPelsWidth: {:?}", dm.dmPelsWidth);
    println!("dmPelsHeight: {:?}", dm.dmPelsHeight);
    println!("dmDisplayFrequency: {:?}", dm.dmDisplayFrequency);
    println!("others");
    println!("dmSpecVersion: {:?}", dm.dmSpecVersion);
    println!("dmDriverVersion: {:?}", dm.dmDriverVersion);
    println!("dmDriverExtra: {:?}", dm.dmDriverExtra);
    println!("dmLogPixels: {:?}", dm.dmLogPixels);
    println!("dmICMMethod: {:?}", dm.dmICMMethod);
}

Crate manifest

[package]
name = "test_refresh"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies.windows]
version = "0.42.0"
features = ["Win32_Foundation", "Win32_Graphics_Gdi"]

Expected behavior

Result: BOOL(1)
dmBitsPerPel: *
dmPelsWidth: 2560
dmPelsHeight: 1440
dmDisplayFrequency: 165
others
dmSpecVersion: *
dmDriverVersion: *
dmDriverExtra: *
dmLogPixels: *
dmICMMethod: *

Actual behavior

Result: BOOL(1)
dmBitsPerPel: 1440
dmPelsWidth: 0
dmPelsHeight: 165
dmDisplayFrequency: 0
others
dmSpecVersion: 1025
dmDriverVersion: 1025
dmDriverExtra: 0
dmLogPixels: 2560
dmICMMethod: 0

Additional comments

No response

[riverar]

Thanks @Skrity, looks like several struct members are incorrectly defined in metadata (DEVMODE_COLOR, DEVMODE_TRUETYPE_OPTION, DEVMODE_COLLATE). Transferring over there!

[mikebattista]

Can you clarify what's broken here? Is the struct defined incorrectly? Or is the API for some reason returning the wrong values?

@riverar you mentioned some enums but the repro doesn't mention any fields that use these enums.

[riverar]

@mikebattista At a quick glance, it appears DEVMODE_COLOR, DEVMODE_TRUETYPE_OPTION, DEVMODE_COLLATE are defined as uint but should be ushort. Depending on the packing, it could be throwing off subsequent fields. Haven't fully triaged this, but the size of the struct in Rust (164 bytes) doesn't match C++ (156 bytes).

If you don't beat me to it, I can possibly take a look later in the evenings.

[mikebattista]

Since you're more familiar with the Rust toolchain, I'll assign to you to make the type changes in enums.json and validate the Rust repro.

[kennykerr]

Since this isn't specific to Rust, it would be great if you have some kind of build validation that compared all struct sizes in metadata against MSVC.

[riverar]

Thanks @Skrity, should see this trickle into the next Rust crate update

[kennykerr]

The DEVMODEA/DEVMODEW structs, in the Windows.Win32.Graphics.Gdi namespace, now have dependencies on the types in the Windows.Win32.System.SystemServices namespace e.g. DEVMODE_DISPLAY_ORIENTATION and DEVMODE_DISPLAY_FIXED_OUTPUT. That seems wrong.

[mikebattista]

Yes that's a bug. I will fix.

[mikebattista]

Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_CENTER added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_DEFAULT added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_STRETCH added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION.DMDO_180 added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION.DMDO_270 added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION.DMDO_90 added
Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION.DMDO_DEFAULT added
Windows.Win32.Graphics.Gdi.DEVMODEA._Anonymous1_e__Union._Anonymous2_e__Struct.dmDisplayFixedOutput...Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT => Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT
Windows.Win32.Graphics.Gdi.DEVMODEA._Anonymous1_e__Union._Anonymous2_e__Struct.dmDisplayOrientation...Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION => Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION
Windows.Win32.Graphics.Gdi.DEVMODEW._Anonymous1_e__Union._Anonymous2_e__Struct.dmDisplayFixedOutput...Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT => Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_FIXED_OUTPUT
Windows.Win32.Graphics.Gdi.DEVMODEW._Anonymous1_e__Union._Anonymous2_e__Struct.dmDisplayOrientation...Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION => Windows.Win32.Graphics.Gdi.DEVMODE_DISPLAY_ORIENTATION
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_CENTER removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_DEFAULT removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_FIXED_OUTPUT.DMDFO_STRETCH removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION.DMDO_180 removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION.DMDO_270 removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION.DMDO_90 removed
Windows.Win32.System.SystemServices.DEVMODE_DISPLAY_ORIENTATION.DMDO_DEFAULT removed