diff --git a/src/tool_paramhlp.c b/src/tool_paramhlp.c
index 67702ebe2..1fe364075 100644
--- a/src/tool_paramhlp.c
+++ b/src/tool_paramhlp.c
@@ -181,6 +181,7 @@ ParameterError str2num(long *val, const char *str)
 {
   if(str) {
     char *endptr;
+    endptr = (void*)0;
     long num;
     errno = 0;
     num = strtol(str, &endptr, 10);