diff --git a/liblog/log_is_loggable.c b/liblog/log_is_loggable.c
index 854ecfa..b4711d2 100644
--- a/liblog/log_is_loggable.c
+++ b/liblog/log_is_loggable.c
@@ -42,7 +42,7 @@
 struct cache {
     const prop_info *pinfo;
     uint32_t serial;
-    char c;
+    unsigned char c;
 };
 
 #define BOOLEAN_TRUE 0xFF