ucrtbase: Add support for x mode in fopen.

dlls/msvcrt/file.c

@@ -1586,6 +1586,13 @@ static int msvcrt_get_flags(const wchar_t* mode, int *open_flags, int* stream_fl
       *open_flags |=  _O_TEXT;
       *open_flags &= ~_O_BINARY;
       break;
+#if _MSVCR_VER>=140
+    case 'x':
+      if(!MSVCRT_CHECK_PMT((*open_flags & (_O_CREAT | _O_APPEND)) == _O_CREAT))
+          return -1;
+      *open_flags |= _O_EXCL;
+      break;
+#endif
     case 'D':
       *open_flags |= _O_TEMPORARY;
       break;

dlls/ucrtbase/tests/misc.c

@@ -1539,6 +1539,54 @@ static void test_fenv(void)
     ok(!except, "expected 0, got %lx\n", except);
 }
 
+static void test_fopen_exclusive( void )
+{
+    char path[MAX_PATH*2];
+    DWORD len;
+    FILE *fp;
+
+    if (!GetProcAddress(GetModuleHandleA("ucrtbase.dll"), "__std_terminate"))
+    {
+        win_skip("skipping fopen x mode tests.\n");
+        return;
+    }
+
+    len = GetTempPathA(MAX_PATH, path);
+    ok(len, "GetTempPathA failed\n");
+    strcat(path, "\\fileexcl.tst");
+
+    fp = fopen(path, "wx");
+    ok(fp != NULL, "creating file with mode wx failed\n");
+    fclose(fp);
+
+    fp = fopen(path, "wx");
+    ok(!fp, "overwrote existing file with mode wx\n");
+    unlink(path);
+
+    fp = fopen(path, "w+x");
+    ok(fp != NULL, "creating file with mode w+x failed\n");
+    fclose(fp);
+
+    fp = fopen(path, "w+x");
+    ok(!fp, "overwrote existing file with mode w+x\n");
+
+    SET_EXPECT(global_invalid_parameter_handler);
+    fp = fopen(path, "rx");
+    CHECK_CALLED(global_invalid_parameter_handler);
+    ok(!fp, "opening file with mode rx succeeded\n");
+    unlink(path);
+
+    SET_EXPECT(global_invalid_parameter_handler);
+    fp = fopen(path, "xw");
+    CHECK_CALLED(global_invalid_parameter_handler);
+    ok(!fp, "creating file with mode xw succeeded\n");
+
+    fp = fopen(path, "wbx");
+    ok(fp != NULL, "creating file with mode wx failed\n");
+    fclose(fp);
+    unlink(path);
+}
+
 START_TEST(misc)
 {
     int arg_c;
@@ -1580,4 +1628,5 @@ START_TEST(misc)
     test_clock();
     test_thread_storage();
     test_fenv();
+    test_fopen_exclusive();
 }