diff --git a/include/inline/stringops.h b/include/inline/stringops.h
index cf5d98fb..b5616081 100644
--- a/include/inline/stringops.h
+++ b/include/inline/stringops.h
@@ -109,7 +109,7 @@ strip_unprintable(char *string)
 			*c2++ = *c;
 			break;
 		default:
-			if (*c < 32)
+			if ((unsigned char)*c < 32)
 				break;
 			*c2++ = *c;
 			last_non_space = c2;