[llvm-branch-commits] [libcxx] [libc++] Implements filebuf unbuffered. (PR #76629)

[Mark de Wever via llvm-branch-commits]

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@@ -276,6 +276,30 @@ private:
   state_type __st_;
   state_type __st_last_;
   ios_base::openmode __om_;
+  // Used to track the currently used mode and track whether the output should
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mordante wrote:

Review note: It might be possible to use other fields to achieve the same goal. Unfortunately there's no implementation documentation for this class. This changes seems the simplest and the easiest to validate. 

https://github.com/llvm/llvm-project/pull/76629