`standalone_sys` should support string constants

[Jake-Shadle]

Which crate is this about?

windows-bindgen

Crate version

0.49.0

Summary

When binding string constants there are 2 issues.

1. String constants are Type::String, which gets resolved to HSTRING, and while it's unlikely, if you don't bind another item that pulls in PCSTR or PCWSTR (the string types that Type::String constants actually get resolved to) then there will be a missing typedef.
2. String constants unconditionally assume that the s! and w! macros are available.

Toolchain version/configuration

No response

Reproducible example

No response

Crate manifest

No response

Expected behavior

The emitted string constants should compile correctly.

Actual behavior

The emitted constants will fail to compile due to the unknown s! or w! macro(s), and possibly due to missing the type aliases for PCSTR and/or PCWSTR.

Additional comments

No response

[kennykerr]

String constants are Type::String, which gets resolved to HSTRING,

That's not the case.

String constants unconditionally assume that the s! and w! macros are available.

Note that this only affects standalone_sys where standalone_win assumes a dependency on the windows-core crate and works fine.

[kennykerr]

I take that back - this changed somewhere along the way. The metadata should only use System.String for HSTRING types. 🙄

[kennykerr]

Much has changed in windows-bindgen since this issue was opened so I'm not sure whether its still relevant. A major update was recently published that you can read about here: #3359

Take it for a spin and let me know if you have any feedback.