diff --git a/constants.c b/constants.c
index 8239355..3a8123c 100644
--- a/constants.c
+++ b/constants.c
@@ -2,6 +2,7 @@
 #include <sys/socket.h>
 #include <fcntl.h>
 #include <poll.h>
+#include <errno.h>
 
 //    printf("x %d\n", x);
 void main() {
@@ -17,4 +18,6 @@ void main() {
     printf("POLLERR         %d\n", POLLERR);
     printf("POLLNVAL        %d\n", POLLNVAL);
     printf("SHUT_RDWR       %d\n", SHUT_RDWR);
+    printf("EAGAIN          %d\n", EAGAIN);
+    printf("EWOULDBLOCK     %d\n", EWOULDBLOCK);
 }