1 files changed, 1 insertions, 0 deletions
diff --git a/regexp.h b/regexp.h
index 27f17e71c9..6de89c9fd2 100644
--- a/regexp.h
+++ b/regexp.h
@@ -240,6 +240,7 @@ and check for NULL.
 #define RXf_SKIPWHITE		0x00000100 /* Pattern is for a split / / */
 #define RXf_START_ONLY		0x00000200 /* Pattern is /^/ */
 #define RXf_WHITE		0x00000400 /* Pattern is /\s+/ */
+#define RXf_NULL		0x40000000 /* Pattern is // */
 
 /* 0x1F800 of extflags is used by (RXf_)PMf_COMPILETIME */
 #define RXf_PMf_LOCALE  	0x00000800 /* use locale */