1 files changed, 1 insertions, 1 deletions

diff --git a/lib/utils_base.h b/lib/utils_base.h
index 04f6370..d69b0da 100644
--- a/lib/utils_base.h
+++ b/lib/utils_base.h
@@ -62,7 +62,7 @@ int check_range(double, range *);
 int get_status(double, thresholds *);
 
 /* All possible characters in a threshold range */
-#define NP_THRESHOLDS_CHARS "0123456789.:@~"
+#define NP_THRESHOLDS_CHARS "-0123456789.:@~"
 
 char *np_escaped_string (const char *);