检查连接打开或关闭?(在 Linux 中的 C 中) [英] Check connection open or closed ?(in C in Linux)

问题描述

在 Linux 的套接字编程中，我需要在套接字中写入数据，但我不知道套接字是打开还是关闭.我如何知道套接字是打开和关闭而不读取?

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 ?

printf("befor read%d
", n);
bzero(buffer, MAX_SIZE_BUFFER);
n = read(sockfd, buffer, MAX_SIZE_BUFFER - 1);
printf("after read%d
", n);
if (n <= 0)
{
    break;
}
printf("befor write%d, s: %d 
", n , sockfd);

n = write(newsockfd, buffer, n);
if (n <= 0)
{
    break;
}

我从 sockfd 读取，我确定这个连接是打开的.什么时候在newsockfd中写入缓冲区我不知道newsockfd是打开还是关闭如何检查newsockfd是否关闭?

I read from sockfd and I sure this connection is open . When to write buffer in newsockfd I don't know newsockfd is open or close how to check newsockfd is closed ?

我知道问题.在写作过程中连接关闭.例如在 500 个连接关闭和程序关闭中写入 1024 个数据.如何避免这种情况?

I know problem . in middle of writing connection closed . for example write 1024 data in 500 connection closed and program closed. how to avoid this ?

推荐答案

我用 send() 代替 write() 处理无信号:

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);
if (n <= 0)
{
    break;
}
n2 = send(newsockfd, buffer, n, MSG_NOSIGNAL);
if (n2 == -1)
{
    close(sockfd);
    close(newsockfd);
    return;
}
if (n2 != n)
{
    break;
}

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