FFI C++ examples under Windows 10 with Visual Studio 2022

[jlfaucher]

Hello
I'm testing the FFI C++ examples under Windows 10 with Visual Studio 2022.
I run this command to build the library (from source v1.0.0)
cargo build -p icu_capi_staticlib --features cpp_default

and then this command from the example directory
cl /std:c++20 /EHsc test.cpp ..\..\..\..\..\target\debug\icu_capi_staticlib.lib userenv.lib advapi32.lib ws2_32.lib bcrypt.lib
(I use std:c++20 because the compiler says so)

Some examples work good, some doesn't.
I'm curious to know if the following problems are just me...

When running locale/test, I get
Created a locale: "s-ES"
Locale did not match expected: "es-ES"
("s-ES" is truncated, works good under MacOs)

When running the segmenter example, I get several warnings like that:
`2022-10-24 14:21:05,150 WARN [icu_provider::error] ICU4X data error: Missing data for locale (key: segmenter/dictionary@1, request: km)``
(same warnings under MacOs)

Thanks for your great work!
Jean-Louis

[sffc]

(1) looks odd. Why would the first character of the string be dropped? @Manishearth (or CC others)

(2) is a known issue. The warnings are harmless and can be ignored. I opened #2781 to print better diagnostics and avoid printing noisy warnings.

[sffc]

Hmm. It looks like the string gets a NUL byte added to it at some point.

@jefgen, this is a MSVC failure in ICU4X. Do you know someone who could take a look?

[jlfaucher]

For information, the C example works correctly.
So the problem seems limited to the management of temporary buffer by Diplomat ?

[jlfaucher]

It's a bad usage of std::string_view in the test case.
::std:string_view must not be used to refer a temporary string.
Use std::string instead.

current: std::string_view actualString = locale.to_string().ok().value();
to be: std::string actualString = locale.to_string().ok().value();

With this change, the test case works correctly when compiling with Visual Studio 2022.

[sffc]

Oh, yeah, that would do it! Good catch.

Want to open a PR to fix it?

[jlfaucher]

ok, I will.