tree_based_check: filter utility for hash lists

1 files changed, 1 insertions, 1 deletions

diff --git a/include/hex_conversion.h b/include/hex_conversion.h
index b31216d..4b97d6d 100644
--- a/include/hex_conversion.h
+++ b/include/hex_conversion.h
@@ -26,7 +26,7 @@ inline int convert_line(char *s) {
         return -1;
     l=strlen(s);
     for (i=0; i<l; i++) {
-        s[i] = toupper(s[i]);
+        s[i] = (char)toupper(s[i]);
         if ((s[i] == '\r' && (l-i<3)) || (s[i] == '\n' && i==l-1)) {
             s[i] = '\0';
             break;