Provide wrappers for APIs which return variable-length strings

[justanotheranonymoususer]

Suggestion

Similar to WIL:
https://github.com/microsoft/wil/wiki/Win32-helpers#predefined-adapters-for-functions-that-return-variable-length-strings

[kennykerr]

There's already good support for paths and environment variables in the Rust Standard Library so I'm not sure this is generally useful for most Rust developers to warrant dedicated support here.

[justanotheranonymoususer]

It's not specifically for env vars, but generally for APIs which return variable-length strings. Examples: * QueryFullProcessImageName * GetModuleFileName * GetWindowsDirectory * GetLongPathName For a specific example that I encountered, take a look at the following code in the rust compiler: https://github.com/rust-lang/rust/blob/279604832887abeaea0cb31c20590c43dea497ae/compiler/rustc_session/src/filesearch.rs#L119-L152 They're using GetModuleFileNameW with a buffer of 1024, and hope for the best. It's wasteful in most cases, and can still fail for really long paths. Ideally, there'd be a wrapper which will start with 260 bytes on the stack (avoiding heap most of the time), and then reallocate if needed, just like WIL does. In order to not have everybody reinvent the wheel, having windows-rs do it (like WIL does) will help have more robust, less buggy software for Windows in rust. Another example is GetLongPathName which I needed recently. I found the normpath crate which wraps it nicely. Look at its implementation: https://github.com/dylni/normpath/blob/d65453fdb39ee4091846732477975fb665b1a7dd/src/windows/mod.rs#L153 It uses the "winapi_path", "winapi_buffered" functions to handle the variable-length returned path. It's 100 lines of subtle, unsafe code. I hope they did it right, but I don't trust any crate author (or myself) to get it right. Ideally, it should be part of a Microsoft crate, either here or in a more high-level crate. I hope it makes sense. Thanks.

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On Fri, Feb 7, 2025 at 4:34 AM Kenny Kerr ***@***.***> wrote: There's already good support for paths and environment variables in the Rust Standard Library so I'm not sure this is generally useful for most Rust developers to warrant dedicated support here. — Reply to this email directly, view it on GitHub <#3475 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMDRPGV5CZJP2YY63WXDST2OQLSVAVCNFSM6AAAAABWUR2IVGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDMNBRG44DGOBSG4> . You are receiving this because you authored the thread.Message ID: ***@***.***>