c - TCP connect() always passes -

i have simple tcp client follows. problem connect() call returns 0 when there no server on other side.

int tcpsend(struct sockaddr_in* ipv4_client, const void* buffer, size_t size) {      int sd_client = 0;     int status = -1;      // grab ipv4 tcp socket.     sd_client = socket(af_inet, sock_stream, 0);     if (sd_client == -1) {         return -1;     }      // make socket non-blocking connect may fail     status = fcntl(sd_client, f_setfl, o_nonblock);     if (status < 0) {         close(sd_client);         return -1;     }      // bind , connect     status = connect(sd_client, (struct sockaddr*)ipv4_client, sizeof(*ipv4_client));     if (status == -1) {         close(sd_client);         return -1;     }      printf("status: %d %s\n", status, strerror(errno)); //// ??? : status = 0 here      // send message server port on machine host.     // ignore fact send might not have sent complete data     status = send(sd_client, buffer, size, 0);  //// consequently sigpipe here     if (status == -1) {         close(sd_client);         return -1;     }      close(sd_client);      return 0; } 

i understand connect() pass if binding succeeds , connection doesn't happen. shouldn't happen when socket made o_nonblock. code passes @ connect() , sigpipe error inside send().

after connect in non-blocking mode need call select() socket fd in writable set, i.e. wait until becomes writable, either (1) check errors on socket via getsockopt(), or (2) call connect() again , check error. after valid start calling send() or recv().