Feature/msg nosignal

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 
-project(msocket LANGUAGES C CXX VERSION 2.0.2)
+project(msocket LANGUAGES C CXX VERSION 2.0.3)
 
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
 set(CMAKE_DISABLE_SOURCE_CHANGES ON)

docs/Doxyfile

@@ -1,6 +1,6 @@
 # Doxyfile for Sphinx + Breathe integration
 PROJECT_NAME           = "msocket"
-PROJECT_NUMBER         = "2.0.2"
+PROJECT_NUMBER         = "2.0.3"
 PROJECT_BRIEF          = "Event-driven socket library for Linux and Windows"
 
 # Input configuration

docs/conf.py

@@ -12,7 +12,7 @@
 project = 'msocket'
 copyright = '2026, Conny Gustafsson'
 author = 'Conny Gustafsson'
-release = '2.0.2'
+release = '2.0.3'
 
 # -- General configuration ---------------------------------------------------
 

include/msocket.h

@@ -305,7 +305,10 @@ msocket_error_t msocket_unix_connect(msocket_t *self, const char *socket_path);
 msocket_error_t msocket_send_to(msocket_t *self, const char *addr, uint16_t port, const void *msg_data, uint32_t msg_len);
 
 /**
- * Sends stream data over an established TCP connection.
+ * Sends stream data over an established TCP or UNIX domain socket connection.
+ *
+ * Transmits with MSG_NOSIGNAL (where supported) to prevent raising SIGPIPE
+ * if the remote peer has closed or disconnected.
  *
  * @param self Pointer to msocket_t instance (configured in MSOCKET_MODE_STREAM).
  * @param msg_data Pointer to data payload.

source/msocket_common.c

@@ -545,7 +545,7 @@ msocket_error_t msocket_send(msocket_t *self, const void *msg_data, uint32_t msg
    const char *p = (const char *)msg_data;
    uint32_t remain = msg_len;
    while (remain > 0u) {
-      int n = (int)send(self->os->tcp_sockfd, p, (int)remain, 0);
+      int n = (int)send(self->os->tcp_sockfd, p, (int)remain, MSG_NOSIGNAL);
       if (n <= 0) {
          return MSOCKET_SOCKET_ERROR;
       }

source/msocket_internal.h

@@ -125,6 +125,10 @@ typedef int os_socket_t;
 
 #endif
 
+#ifndef MSG_NOSIGNAL
+# define MSG_NOSIGNAL                0
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 // PLATFORM THREADING & SYNC
 //////////////////////////////////////////////////////////////////////////////

tests/testsuite_msocket_loopback.c

@@ -219,10 +219,78 @@ static void test_udp_loopback(CuTest *tc)
    msocket_sem_delete(g_sem_udp_received);
 }
 
+#define TCP_PORT_SIGPIPE 19878u
+
+static void test_tcp_send_to_closed_peer_returns_error_without_sigpipe(CuTest *tc)
+{
+   g_sem_client_connected = msocket_sem_new(0u);
+   g_accepted_peer = NULL;
+
+   msocket_t *srv = msocket_new(MSOCKET_ADDR_INET);
+   CuAssertPtrNotNull(tc, srv);
+   msocket_error_t rc = msocket_listen(srv, MSOCKET_MODE_STREAM, TCP_PORT_SIGPIPE, "127.0.0.1");
+   CuAssertIntEquals(tc, MSOCKET_NO_ERROR, rc);
+
+   msocket_handler_t srv_handler;
+   memset(&srv_handler, 0, sizeof(srv_handler));
+
+   accept_thread_arg_t ctx = { srv, &srv_handler };
+   msocket_thread_t *accept_thread = msocket_thread_create(accept_worker, &ctx);
+   CuAssertPtrNotNull(tc, accept_thread);
+
+   /* Start client */
+   msocket_t *cli = msocket_new(MSOCKET_ADDR_INET);
+   CuAssertPtrNotNull(tc, cli);
+
+   msocket_handler_t cli_handler;
+   memset(&cli_handler, 0, sizeof(cli_handler));
+   cli_handler.stream_connected = client_on_connected;
+   msocket_set_handler(cli, &cli_handler, NULL);
+
+   rc = msocket_connect(cli, "127.0.0.1", TCP_PORT_SIGPIPE);
+   CuAssertIntEquals(tc, MSOCKET_NO_ERROR, rc);
+
+   /* Wait for client connected */
+   int attempts = 0;
+   while (msocket_sem_test(g_sem_client_connected) <= 0 && attempts++ < 50) {
+      msocket_sleep_ms(20u);
+   }
+   CuAssertTrue(tc, attempts < 50);
+
+   /* Wait for accept thread to finish accepting peer */
+   msocket_thread_join(accept_thread);
+   msocket_thread_delete(accept_thread);
+   CuAssertPtrNotNull(tc, g_accepted_peer);
+
+   /* Close the client abruptly */
+   msocket_close(cli);
+   msocket_delete(cli);
+   msocket_sleep_ms(50u);
+
+   /* Sending to the closed peer from server side should not trigger SIGPIPE or crash */
+   (void)msocket_send(g_accepted_peer, "Test1", 5u);
+   msocket_sleep_ms(50u);
+   (void)msocket_send(g_accepted_peer, "Test2", 5u);
+
+   /* Cleanup */
+   if (g_accepted_peer != NULL) {
+      msocket_close(g_accepted_peer);
+      msocket_delete(g_accepted_peer);
+      g_accepted_peer = NULL;
+   }
+
+   msocket_close(srv);
+   msocket_delete(srv);
+
+   msocket_sem_delete(g_sem_client_connected);
+}
+
 CuSuite *testsuite_msocket_loopback(void)
 {
    CuSuite *suite = CuSuiteNew();
    SUITE_ADD_TEST(suite, test_tcp_loopback);
    SUITE_ADD_TEST(suite, test_udp_loopback);
+   SUITE_ADD_TEST(suite, test_tcp_send_to_closed_peer_returns_error_without_sigpipe);
    return suite;
 }
+