diff --git a/perl.h b/perl.h
index d967c494938f..65e54cbb9bc8 100644
--- a/perl.h
+++ b/perl.h
@@ -6755,17 +6755,10 @@ the plain locale pragma without a parameter (S<C<use locale>>) is in effect.
                                     LOCALE_TERM_POSIX_2008_;                \
                                 } STMT_END
 #endif
-#if ! (   defined(USE_LOCALE)                                               \
+#if (   defined(USE_LOCALE)                                                 \
        &&    defined(USE_LOCALE_THREADS)                                    \
        && (  ! defined(USE_THREAD_SAFE_LOCALE)))
 
-/* The whole expression just above was complemented, so here we have no need
- * for thread synchronization, most likely it would be that this isn't a
- * threaded build. */
-#  define LOCALE_READ_LOCK          NOOP
-#  define LOCALE_READ_UNLOCK        NOOP
-#else
-
    /* Here, we will need critical sections in locale handling, because one or
     * more of the above conditions are true.  This could be because the
     * platform doesn't have thread-safe locales, or that at least one of the
@@ -6845,6 +6838,11 @@ the plain locale pragma without a parameter (S<C<use locale>>) is in effect.
 #  define SETLOCALE_UNLOCK              NOOP
 #endif
 
+/* Currently, the read lock is an exclusive lock */
+#define LOCALE_READ_LOCK                SETLOCALE_LOCK
+#define LOCALE_READ_UNLOCK              SETLOCALE_UNLOCK
+
+
 #ifndef LC_NUMERIC_LOCK
 #  define LC_NUMERIC_LOCK(cond)   NOOP
 #  define LC_NUMERIC_UNLOCK       NOOP