为winsock recvfrom设置超时 [英] Set timeout for winsock recvfrom
本文介绍了为winsock recvfrom设置超时的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在尝试在端口上尝试 recvfrom() 16 毫秒后设置一个阻塞套接字以超时.平台是 Windows.我在网上看了很多例子,看起来很简单,我似乎无法让它工作.任何帮助将不胜感激!
I'm trying to set up a blocking socket to timeout after 16 ms of trying to recvfrom() on a port. Platform is Windows. I've looked at tons of examples online and it seems really simple I just can't seem to get it to work. Any help would be appreciated!
#include <winsock2.h>
#include <string>
#pragma comment(lib, "ws2_32.lib")
#define PORT_NUM 8001
int main(void)
{
std::string localIP;
sockaddr_in localAddr;
sockaddr_in remoteAddr;
hostent* localhost;
char buffer[1024];
WSADATA wsData;
int result = WSAStartup(MAKEWORD(2,2), &wsData); // winsock version 2
localhost = gethostbyname("");
localIP = inet_ntoa(*(in_addr*)*localhost->h_addr_list);
localAddr.sin_family = AF_INET;
localAddr.sin_port = htons(PORT_NUM); // Set Port Number
localAddr.sin_addr.s_addr = inet_addr(localIP.c_str()); // Set IP Address
int mHandle = WSASocket(AF_INET, SOCK_DGRAM, IPPROTO_UDP, NULL, 0, 0);
if(mHandle == INVALID_SOCKET)
return 1;
if(bind(mHandle, (SOCKADDR*)&localAddr, sizeof(localAddr)) == SOCKET_ERROR)
return 1;
timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 1600;
// Set Timeout for recv call
if(setsockopt(mHandle, SOL_SOCKET, SO_RCVTIMEO,
reinterpret_cast<char*>(&tv), sizeof(timeval)))
return 1;
int length = sizeof(remoteAddr);
// <-- Blocks here forever
recvfrom(mHandle, buffer, 1024, 0, (SOCKADDR*)&remoteAddr, &length);
return 0;
}
/* I've also tried passing the time like so:
int ms = 16;
if(setsockopt(mHandle, SOL_SOCKET, SO_RCVTIMEO, reinterpret_cast<char*>(&ms), sizeof(int)))
return 1; */
推荐答案
我查看了 select 函数,正如 laura 所说我应该做的,让它真正轻松地工作!谢谢!
I looked into the select function and as laura said I should do and got it to work real easily! Thanks!
fd_set fds ;
int n ;
struct timeval tv ;
// Set up the file descriptor set.
FD_ZERO(&fds) ;
FD_SET(mHandle, &fds) ;
// Set up the struct timeval for the timeout.
tv.tv_sec = 10 ;
tv.tv_usec = 0 ;
// Wait until timeout or data received.
n = select ( mHandle, &fds, NULL, NULL, &tv ) ;
if ( n == 0)
{
printf("Timeout..
");
return 0 ;
}
else if( n == -1 )
{
printf("Error..
");
return 1;
}
int length = sizeof(remoteAddr);
recvfrom(mHandle, buffer, 1024, 0, (SOCKADDR*)&remoteAddr, &length);
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