diff --git a/man2/ipc.2 b/man2/ipc.2
index f505fa1c9..4ce29ca69 100644
--- a/man2/ipc.2
+++ b/man2/ipc.2
@@ -27,6 +27,7 @@
 ipc \- System V IPC system calls
 .SH SYNOPSIS
 .nf
+.BR "#include <linux/ipc.h>" "        /* Definition of needed constants */"
 .BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
 .B #include <unistd.h>
 .PP