Re: [PATCH v2 0/1] MR6644: Draft: msvcrt: Initialize locale data in new threads.

[Piotr Caban (＠piotr)]

Piotr Caban (@piotr) commented about dlls/msvcrt/thread.c:
> #if _MSVCR_VER >= 140
>          ptr->module = NULL;
>  #endif
> +        _setmbcp(_MB_CP_ANSI);
> You can't call _setmbcp() here - it might modify other thread mbcp when global (non per-thread) settings are used. The bug is caused by using uninitialized locale cache. The simplest solution is to set:
ptr->cached_locale[0] = 'C';
ptr->cached_locale[1] = 0;

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https://gitlab.winehq.org/wine/wine/-/merge_requests/6644#note_84575