1 files changed, 33 insertions, 0 deletions
diff --git a/src/wctype/towlower.c b/src/wctype/towlower.c
new file mode 100644
index 00000000..8e5254d8
--- /dev/null
+++ b/src/wctype/towlower.c
@@ -0,0 +1,33 @@
+#include <wctype.h>
+#include "wchar.h"
+#include "stdlib.h"
+#include "nonstd/assert.h"
+
+/** convert a wide uppercase letter to lowercase **/
+wint_t towlower(wint_t wc)
+{
+	ASSERT_REPRESENTABLE(wc, WCHAR_MIN, WCHAR_MAX, "wchar_t", WEOF);
+
+	if (!iswupper(wc)) {
+		return wc;
+	}
+
+	wctrans_t trans = wctrans("tolower");
+	return towctrans(wc, trans);
+}
+
+/***
+The fn(towlower) function converts a wide uppercase letter to its equivalent
+lowercase letter in the current locale.
+***/
+
+/* RETURN(arg(c)): arg(wc) was not a wide uppercase letter or it has no equivalent lowercase letter */
+/* RETURN: arg(wc) converted to lowercase */
+
+/* UNSPECIFIED: - */
+/* IMPLEMENTATION: - */
+/* LOCALE: LC_CTYPE */
+
+/*
+STDC(199409)
+*/