windows - 如何将OsString传递给Win32 API调用

Question

我使用了xxxA版本的调用来使用CString编写此代码。现在，我想使用xxxW版本，无法解决如何将OsString传递给调用的问题。

let cname = OsString::from("my backend class");
let brush = CreateSolidBrush(RGB(0, 0, 0));
let cl = WNDCLASSW {
    style: 0,
    lpfnWndProc: Some(callback),
    cbClsExtra: 0,
    cbWndExtra: std::mem::size_of::<&i32>() as i32,
    hInstance: handle,
    hIcon: 0 as HICON,
    hCursor: LoadCursorW(std::ptr::null_mut(), IDC_ARROW),
    hbrBackground: brush, //(COLOR_WINDOW + 1) as HBRUSH,
    lpszMenuName: 0 as LPWSTR,
    lpszClassName: cname.as_ptr(), <<<=======
};

OsString没有as_ptr()方法。我不应该使用OsString吗？如果没有，我应该怎么用？

Answer 1

每the documentation:

On Windows, OsStr implements the std::os::windows::ffi::OsStrExt trait, which provides an encode_wide method. This provides an iterator that can be collected into a vector of u16.

encode_wide 的文档还指出:

Note that the encoding does not add a final null terminator.

因此:

use std::os::windows::ffi::OsStrExt;

let cname = OsStr::new("my backend class")
    .encode_wide()
    .chain(Some(0)) // add NULL termination
    .collect::<Vec<_>>();

// and then call cname.as_ptr() as you are currently doing