[Bug 51846] New: Standard library call fopen(..., "wx") not recognized - causes destruction of data

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51846

Bug ID: 51846
           Summary: Standard library call fopen(..., "wx") not recognized
                    - causes destruction of data
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: msvcrt
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 70740
  --> https://bugs.winehq.org/attachment.cgi?id=70740
open_excl.cpp

wine-6.16 (Staging)

When running a program that uses the standard (since C11 and C++17) fopen()
mode "wx" to guarantee that opening a file for writing fails if it already
exists, I noticed that wine can't handle that mode. Instead, it prints
"0104:err:msvcrt:msvcrt_get_flags incorrect mode flag: x" and successfully
opens the file - even if it already exists - which destroys the content of the
existing file.

I'm attaching the source code to a small C++17 program that works as expected
when compiled with Visual Studio 2019 (/std:c++17) and running it on Windows 10
natively.