diff --git a/tochar16_unicode.c b/tochar16_unicode.c
index 772e962..fe99803 100644
--- a/tochar16_unicode.c
+++ b/tochar16_unicode.c
@@ -3,10 +3,14 @@
 
 #include "build.h"
 
-char32_t* tochar32_unicode(char32_t d[1], unsigned int uc) {
-    if (uc <= 0x10ffff && (uc < 0xd800 || uc > 0xdfff)) {
+char16_t* tochar16_unicode(char16_t d[2], unsigned int uc) {
+    if (uc <= 0xffff) {
         *(d++) = uc;
-    } else return 0;
+    } else if (uc <= 0x10ffff && (uc < 0xd800 || uc > 0xdfff)) {
+        uc    -= 0x010000;
+        *(d++) = 0xd800 | (uc&0x0ffc00)>>10;
+        *(d++) = 0xdc00 | (uc&0x03ff);
+    } else d = 0;
 
     return d;
 }