我用
select()
制作了一个简单的服务器客户端程序,但问题是客户端没有收到欢迎消息。我之前在没有 select()
的情况下这样做过几次并且它有效,但突然之间它不想在使用 select()
时工作。我做错了什么?
服务器:
#define MAX_CLIENTS 10
int main()
{
system("clear");
printf("***SERVER STARTED***\n");
int master_socket = socket(AF_INET, SOCK_STREAM, 0);
fd_set fdsForReading;
struct sockaddr_in address;
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8888);
bind(master_socket, (struct sockaddr *)&address, sizeof(address));
listen(master_socket, 3);
while (1)
{
FD_ZERO(&fdsForReading); // Clearing the file descriptor set
FD_SET(master_socket, &fdsForReading); // Add master_socket to file descriptor set
printf("Monitoring for connections...\n");
select(master_socket + 1, &fdsForReading, NULL, NULL, NULL);
int accepted_socket = accept(master_socket, (struct sockaddr *)&address, sizeof(address));
printf("[+] New connection accepted\n");
char buffer[125] = "Welcome to my server";
send(accepted_socket, buffer, sizeof(buffer), 0);
printf("End of while loop\n");
}
}
客户:
int main()
{
system("clear");
int clientSocket = socket(AF_INET, SOCK_STREAM, 0), x;
struct sockaddr_in serverAddress;
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(8888);
serverAddress.sin_addr.s_addr = INADDR_ANY;
connect(clientSocket, (struct sockaddr *)&serverAddress, sizeof(serverAddress));
char serverResponse[125];
recv(clientSocket, &serverResponse, sizeof(serverResponse), 0);
printf("test: %s\n", serverResponse);
scanf("%d", &x);
close(clientSocket);
}
&serverResponse
应该是serverResponse
recv
收到的字符数可能少于您发送的字符数,因此您应该检查收到的字符数,并可能将收到的字符连接起来,直到收到完整的消息。\0
)一起使用,则需要添加 printf("%s", ...
。在您的情况下,您实际上发送了 125
char
,即使字符串要短得多。你可能不应该这样做。这将发送字符串+空终止字符:
send(accepted_socket, buffer, strlen(buffer) + 1, 0);
accept
的第三个参数应该是socklen_t *
- 而不是sizeof(address)
。例子:
socklen_t addrlen = sizeof address;
int accepted_socket = accept(master_socket, (struct sockaddr *)&address, &addrlen);
通过这些更改,如果没有发生错误,客户端将收到良好的问候语 - 但是当您添加错误检查时,您将看到这种情况下问题出在哪里。