我正在通过Winsock创建一个UDP (AF_INET
,SOCK_DGRAM
,IPPROTO_UDP
),并尝试在这个套接字上执行recvfrom
,但它总是返回-1,并且我得到了WSAEINVAL (10022)。为什么?
当我bind()
端口时,这是不会发生的,但我读到绑定客户端的套接字是非常差劲的。
我正在向我的服务器发送数据,它会响应,或者至少会尝试。
Inc::STATS CConnection::_RecvData(sockaddr* addr, std::string &strData)
{
int ret; // return code
int len; // length of the data
int fromlen; // sizeof(sockaddr)
char *buffer; // will hold the data
char c;
//recv length of the message
fromlen = sizeof(sockaddr);
ret = recvfrom(m_InSock, &c, 1, 0, addr, &fromlen);
if(ret != 1)
{
#ifdef __MYDEBUG__
std::stringstream ss;
ss << WSAGetLastError();
MessageBox(NULL, ss.str().c_str(), "", MB_ICONERROR | MB_OK);
#endif
return Inc::ERECV;
}
...
这是我在几分钟前写的一个工作示例,它不需要在客户端调用bind()
就可以工作:
#pragma comment(lib, "Ws2_32.lib")
#define WIN32_LEAN_AND_MEAN
#include <WS2tcpip.h>
#include <Windows.h>
#include <iostream>
using namespace std;
int main()
{
SOCKET sock;
addrinfo* pAddr;
addrinfo hints;
sockaddr sAddr;
int fromlen;
const char czPort[] = "12345";
const char czAddy[] = "some ip";
WSADATA wsa;
unsigned short usWSAVersion = MAKEWORD(2,2);
char Buffer[22] = "TESTTESTTESTTESTTEST5";
int ret;
//Start WSA
WSAStartup(usWSAVersion, &wsa);
//Create Socket
sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
//Resolve host address
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_protocol = IPPROTO_UDP;
hints.ai_socktype = SOCK_DGRAM;
if(getaddrinfo(czAddy, czPort, &hints, &pAddr))
{
std::cerr << "Could not resolve address...\n";
std::cin.get();
return 1;
}
//Start Transmission
while(1)
{
ret = sendto(sock, Buffer, sizeof(Buffer), 0, pAddr->ai_addr,
pAddr->ai_addrlen);
if(ret != sizeof(Buffer))
{
std::cerr << "Could not send data\n";
std::cin.get();
return 1;
}
fromlen = sizeof(SOCKADDR);
ret = recvfrom(sock, Buffer, sizeof(Buffer), 0, &sAddr, &fromlen);
if(ret != sizeof(Buffer))
{
std::cout << "Could not receive data - error: " <<
WSAGetLastError() << std::endl;
std::cin.get();
return 1;
}
Buffer[ret-1] = '\0';
std::cout << "Received: " << Buffer << std::endl;
}
return 0;
}
https://stackoverflow.com/questions/3057029
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