[KERNEL32_VISTA] Implement LCIDToLocaleName

dll/win32/kernel32/kernel32_vista/CMakeLists.txt

@@ -12,6 +12,7 @@ list(APPEND SOURCE
     GetTickCount64.c
     GetUserDefaultLocaleName.c
     InitOnce.c
+    LCIDToLocaleName.c
     LocaleNameToLCID.c
     sync.c
     vista.c)

dll/win32/kernel32/kernel32_vista/LCIDToLocaleName.c

@@ -0,0 +1,59 @@
+/*
+ * PROJECT:     ReactOS Win32 Base API
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of LCIDToLocaleName
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include "k32_vista.h"
+#include <ndk/rtlfuncs.h>
+
+int
+WINAPI
+LCIDToLocaleName(
+    _In_ LCID Locale,
+    _Out_writes_opt_(cchName) LPWSTR lpName,
+    _In_ int cchName,
+    _In_ DWORD dwFlags)
+{
+    WCHAR Buffer[LOCALE_NAME_MAX_LENGTH];
+    UNICODE_STRING LocaleNameString;
+    DWORD RtlFlags = 0;
+    NTSTATUS Status;
+
+    if (cchName < 0)
+    {
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return 0;
+    }
+
+    if (dwFlags & LOCALE_ALLOW_NEUTRAL_NAMES)
+    {
+        RtlFlags |= RTL_LOCALE_ALLOW_NEUTRAL_NAMES;
+    }
+
+    if (lpName != NULL)
+    {
+        cchName = min(cchName, LOCALE_NAME_MAX_LENGTH);
+        LocaleNameString.Buffer = lpName;
+        LocaleNameString.Length = 0;
+        LocaleNameString.MaximumLength = (USHORT)(cchName * sizeof(WCHAR));
+    }
+    else
+    {
+        LocaleNameString.Buffer = Buffer;
+        LocaleNameString.Length = 0;
+        LocaleNameString.MaximumLength = sizeof(Buffer);
+    }
+
+    /* Call the RTL function */
+    Status = RtlLcidToLocaleName(Locale, &LocaleNameString, RtlFlags, FALSE);
+    if (!NT_SUCCESS(Status))
+    {
+        SetLastError(RtlNtStatusToDosError(Status));
+        return 0;
+    }
+
+    /* Return the length including the terminating null */
+    return (LocaleNameString.Length / sizeof(WCHAR)) + 1;
+}

dll/win32/kernel32/kernel32_vista/kernel32_vista.spec

@@ -44,6 +44,7 @@
 @ stdcall GetUILanguageInfo(long wstr wstr ptr ptr)
 @ stdcall GetUserDefaultLocaleName(wstr long)
 @ stdcall GetUserPreferredUILanguages(long ptr wstr ptr)
+@ stdcall LCIDToLocaleName(long wstr long long)
 @ stdcall LocaleNameToLCID(wstr long)
 @ stdcall OpenFileById(ptr ptr long long ptr long)
 @ stdcall QueryFullProcessImageNameA(ptr long str ptr)

dll/win32/kernel32/winnls/string/locale.c

@@ -1439,6 +1439,7 @@ LCID WINAPI LocaleNameToLCID( LPCWSTR name, DWORD flags )
 #endif
 
 
+#if 0 // See kernel32_vista
 /***********************************************************************
  *           LCIDToLocaleName  (KERNEL32.@)
  */
@@ -1449,6 +1450,7 @@ INT WINAPI LCIDToLocaleName( LCID lcid, LPWSTR name, INT count, DWORD flags )
     return GetLocaleInfoW( lcid, LOCALE_SNAME | LOCALE_NOUSEROVERRIDE, name, count );
 }
 #endif
+#endif
 
 
 /******************************************************************************