From 815c06f2f727e8a66372ad71e050165c429d4eac Mon Sep 17 00:00:00 2001
From: Erik Dubbelboer <erik@dubbelboer.com>
Date: Wed, 11 Apr 2012 17:04:31 +0200
Subject: [PATCH] added explanation for the magic 511 backlog number

---
 src/anet.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/anet.c b/src/anet.c
index ba4e6cce..434d945c 100644
--- a/src/anet.c
+++ b/src/anet.c
@@ -262,7 +262,11 @@ static int anetListen(char *err, int s, struct sockaddr *sa, socklen_t len) {
         close(s);
         return ANET_ERR;
     }
-    if (listen(s, 511) == -1) { /* the magic 511 constant is from nginx */
+
+    /* Use a backlog of 512 entries. We pass 511 to the listen() call because
+     * the kernel does: backlogsize = roundup_pow_of_two(backlogsize + 1);
+     * which will thus give us a backlog of 512 entries */
+    if (listen(s, 511) == -1) {
         anetSetError(err, "listen: %s", strerror(errno));
         close(s);
         return ANET_ERR;
-- 
GitLab