diff --git a/pcreposix.c b/pcreposix.c
index f024423..dcc13ef 100644
--- a/pcreposix.c
+++ b/pcreposix.c
@@ -364,6 +364,7 @@ start location rather than being passed as a PCRE "starting offset". */
 
 if ((eflags & REG_STARTEND) != 0)
   {
+  if (pmatch == NULL) return REG_INVARG; 
   so = pmatch[0].rm_so;
   eo = pmatch[0].rm_eo;
   }