From 9cd56ab66ceb1fd401cccc2814492587f738e192 Mon Sep 17 00:00:00 2001
From: "andrey.bychkov" <andrey@signalmodelling.ru>
Date: Wed, 5 Aug 2026 17:38:12 +0300
Subject: [PATCH] fix(PIEthernet): check open() return value with >= 0 instead
 of != 0

open() returns -1 on error. The check fd != 0 treated -1 as a
valid fd (since -1 != 0 is true), causing devctl(-1, ...) and
close(-1) on QNX. Fixed to fd >= 0.
---
 libs/main/io_devices/piethernet.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libs/main/io_devices/piethernet.cpp b/libs/main/io_devices/piethernet.cpp
index ad4a08b3..a1245cc1 100644
--- a/libs/main/io_devices/piethernet.cpp
+++ b/libs/main/io_devices/piethernet.cpp
@@ -383,7 +383,7 @@ void PIEthernet::applyBuffers() {
 
 void PIEthernet::applyTimeout(int fd, int opt, PISystemTime tm) {
 	if (fd == 0) return;
-	// piCoutObj << "setReadIsBlocking" << yes;
+		// piCoutObj << "setReadIsBlocking" << yes;
 #ifdef WINDOWS
 	DWORD _tm = tm.toMilliseconds();
 #else
@@ -1234,7 +1234,7 @@ PIEthernet::InterfaceList PIEthernet::interfaces() {
 #	  ifdef QNX
 #		ifndef BLACKBERRY
 			int fd = ::open((PIString("/dev/io-net/") + ci.name).dataAscii(), O_RDONLY);
-			if (fd != 0) {
+			if (fd >= 0) {
 				nic_config_t nic;
 				devctl(fd, DCMD_IO_NET_GET_CONFIG, &nic, sizeof(nic), 0);
 				::close(fd);