Are A or W APIs recommended?

[aliceeatsacarrot]

Hello,

I am excited about the UTF-8 support. The page mentions "Until recently, Windows has emphasized "Unicode" -W variants over -A APIs." Does this mean the ANSI functions are now preferred over the WCHAR ones? For a new application wanting to support multiple languages, which of calling the UTF-8 APIs or the UTF-16LE ones is recommended? Would it be possible to update the page with the information?

Thank you!

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Document Details

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• ID: 77a994ff-cdad-3cbc-11c3-626285d3cb7e
• Version Independent ID: 6fcd9265-4bfc-657a-9177-7c958f1b4b06
• Content: Use the Windows UTF-8 code page - Windows apps
• Content Source: hub/apps/design/globalizing/use-utf8-code-page.md
• Product: uwp
• Technology: design
• GitHub Login: @Karl-Bridge-Microsoft
• Microsoft Alias: kbridge

[Paul-Dempsey]

While UTF-8 now works, and could be convenient for x-platform code, WIndows is still at its base a 16-bit Unicode system and using A APIs always involves a runtime conversion (small but nonzero performance impact). So, depends on your codebase and specific app requirements. UTF-8 is still relatively new, and there are likely interesting edge cases and potential interop issues that could be problematic. (e.g. low-level file system edge cases with nonconforming Unicode sequences.)

[jaigak]

Another thing to note is the A variants are not necessarily UTF-8 - they are whatever code page set on the system or manifested for your application. Converting UTF-8 to UTF-16 yourself and then calling the W variants is more reliable if you are not aware of the settings.