Check connection open or closed ?(in C in Linux)

Question

In socket programming in Linux I need to write data in socket but I don\'t know socket is open or close . how to I know that socket is open and close without read ?

Answer 1

I use send() instead write() that handle no signal :

bzero(buffer, MAX_SIZE_BUFFER);
n = read(sockfd, buffer, MAX_SIZE_BUFFER - 1);
printf("after read%d\n", n);
if (n <= 0)
{
    break;
}
n2 = send(newsockfd, buffer, n, MSG_NOSIGNAL);
if (n2 == -1)
{
    close(sockfd);
    close(newsockfd);
    return;
}
if (n2 != n)
{
    break;
}