diff --git a/configure.ac b/configure.ac
index be817b1..34a600a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@ if test "$enable_memcached" = "yes"; then
 fi
 
 AC_DEFINE([DEFAULT_PORT], [4000], [The default port number if not specified in the config file])
-AC_DEFINE([MAX_RECV_LEN], [1024])
+AC_DEFINE([MAX_RECV_LEN], [1024], [The maximum length of the recv() queue in bytes])
 
 PKG_CHECK_MODULES([GIO], gio-2.0)
 PKG_CHECK_MODULES([GLIB], glib-2.0)