diff --git a/inc/stdlib.h b/inc/stdlib.h
index 929c99e..d702748 100644
--- a/inc/stdlib.h
+++ b/inc/stdlib.h
@@ -35,8 +35,7 @@ typedef struct lldiv_t {
 
 #define RAND_MAX 65536
 
-#define MB_LEN_MAX 4
-#define MB_CUR_MAX 4
+#define MB_CUR_MAX 5
 
 // Microsoft extension, COUNTOF(x) counts array elements
 #ifndef COUNTOF
diff --git a/inc/uchar.h b/inc/uchar.h
index 0871202..f4eb23c 100644
--- a/inc/uchar.h
+++ b/inc/uchar.h
@@ -12,7 +12,7 @@ struct mbstate_t {
     union {
         char16_t leftover;
         char16_t high_surrogate;
-    }
+    };
 };
 
 size_t mbrtoc16(
diff --git a/src/code/uchar.c b/src/code/uchar.c
index e4773a4..3a01b97 100644
--- a/src/code/uchar.c
+++ b/src/code/uchar.c
@@ -82,10 +82,11 @@ size_t c16rtomb(
     }
     else goto invalid_char;
     // Write the codepoint that we decided to write to multibyte string
-    int written_len = utf8_chenc(s, 4, codepoint_to_write);
+    int written_len = utf8_chenc((char8_t *)s, 4, codepoint_to_write);
     if(written_len < 0) {
         goto invalid_char;
     }
+    s[written_len] = 0;
     return (size_t)written_len;
 invalid_char:
     errno = EILSEQ;