diff --git a/socket/socket_sctp6b.c b/socket/socket_sctp6b.c
index 9e107e4..8995eb8 100644
--- a/socket/socket_sctp6b.c
+++ b/socket/socket_sctp6b.c
@@ -1,4 +1,3 @@
-#define _POSIX_SOURCE
 #include <sys/types.h>
 #ifndef __MINGW32__
 #include <unistd.h>
diff --git a/socket/socket_tcp6b.c b/socket/socket_tcp6b.c
index f563b5b..2910212 100644
--- a/socket/socket_tcp6b.c
+++ b/socket/socket_tcp6b.c
@@ -1,4 +1,3 @@
-#define _POSIX_SOURCE
 #include <sys/types.h>
 #ifndef __MINGW32__
 #include <unistd.h>
diff --git a/socket/socket_udp6.c b/socket/socket_udp6.c
index b34df7f..72b3971 100644
--- a/socket/socket_udp6.c
+++ b/socket/socket_udp6.c
@@ -1,4 +1,3 @@
-#define _POSIX_SOURCE
 #include <sys/types.h>
 #ifndef __MINGW32__
 #include <unistd.h>