diff --git a/core/src-c/runes.c b/core/src-c/runes.c
index 7a7062d..b545c59 100644
--- a/core/src-c/runes.c
+++ b/core/src-c/runes.c
@@ -76,12 +76,12 @@ rune_t rr_extract_utf8(const char *string, usz_t offset, usz_t *increase)
     if(string[offset] == 0x00)
         return ZERO;
     
-    usz_t                       offset_into_rune                = rr_distance_to_last_utf8_rune_start(string, offset);
+    isz_t                       offset_into_rune                = rr_distance_to_last_utf8_rune_start(string, offset);
     if(offset_into_rune < 0)
         return ZERO;
     offset                         -= offset_into_rune;
 
-    usz_t                       rune_length                     = rr_identify_utf8_rune_length(string, offset);
+    isz_t                       rune_length                     = rr_identify_utf8_rune_length(string, offset);
     if(rune_length < 0)
         return ZERO;