diff --git a/mongoose.c b/mongoose.c
index e91bb021..6804a8a3 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -2976,7 +2976,8 @@ static void mg_set_non_blocking_mode(SOCKET fd) {
 #elif MG_ARCH == MG_ARCH_AZURERTOS
   fcntl(fd, F_SETFL, O_NONBLOCK);
 #else
-  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK | FD_CLOEXEC);
+  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);  // Set non-blocking mode
+  fcntl(fd, F_SETFD, FD_CLOEXEC);                       // Set close-on-exec
 #endif
 }
 
diff --git a/src/sock.c b/src/sock.c
index 4962caa9..6725a075 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -134,7 +134,8 @@ static void mg_set_non_blocking_mode(SOCKET fd) {
 #elif MG_ARCH == MG_ARCH_AZURERTOS
   fcntl(fd, F_SETFL, O_NONBLOCK);
 #else
-  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK | FD_CLOEXEC);
+  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);  // Set non-blocking mode
+  fcntl(fd, F_SETFD, FD_CLOEXEC);                       // Set close-on-exec
 #endif
 }