From 3b2f3c6d8a5b361c89e4fcc3ccebe126dc9a45f9 Mon Sep 17 00:00:00 2001
From: "Roger A. Light" <roger@atchoo.org>
Date: Fri, 7 Apr 2023 19:29:13 +0100
Subject: [PATCH] Windows: Increase connection limit to 8192 where supported.

Closes #2732. Thanks to zhousongsong.
---
 ChangeLog.txt   | 2 ++
 src/mosquitto.c | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/ChangeLog.txt b/ChangeLog.txt
index 11c0972b..75a03b18 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -7,6 +7,8 @@ Broker:
   assertions removed. Closes #2708.
 - Fix default settings incorrectly allowing TLS v1.1. Closes #2722.
 - Use line buffered mode for stdout. Closes #2354. Closes #2749.
+- Fix connections being limited to 2048 on Windows. The limit is now 8192,
+  where supported. Closes #2732.
 
 Client library:
 - Use CLOCK_BOOTTIME when available, to keep track of time. This solves the
diff --git a/src/mosquitto.c b/src/mosquitto.c
index 4dfd2bde..431254d8 100644
--- a/src/mosquitto.c
+++ b/src/mosquitto.c
@@ -484,7 +484,12 @@ int main(int argc, char *argv[])
 #endif
 
 #ifdef WIN32
-	_setmaxstdio(2048);
+	if(_setmaxstdio(8192) != 8192){
+		/* Old limit was 2048 */
+		if(_setmaxstdio(2048) != 2048){
+			log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Unable to increase maximum allowed connections. This session may be limited to 512 connections.");
+		}
+	}
 #endif
 
 	memset(&db, 0, sizeof(struct mosquitto_db));