此前已经提出过这个问题 Winsock recv() does not block和 在这里C++ Winsock recv not blocking我已经完成了解决方案，但无济于事。 我的方案如下：
我已在VC707 FPGA套件中设置了LWIP服务器，并在我的PC上安装了Windows客户端。客户端将一些数据发送到服务器，然后进入无限循环，等待从服务器recv（）数据。
另一方面，服务器从客户端接收数据，调用数据处理操作，然后发回数据。
我在这里面临的问题是，在服务器收到数据之后，整个过程大约需要1分钟，并发布它将发送数据。但是，客户端的recv（）函数等待大约30-35秒的数据（由watch监视）然后返回-1和套接字错误10057，在早期的情况下为10060，这意味着连接已经终止。
请让我知道我在哪里以及我做错了什么。
client.c：
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <conio.h>
#pragma comment(lib,"ws2_32.lib")
#define DEFAULT_PORT "9881"
#define DEFAULT_BUFLEN 1460
//#define DEFAULT_BUFLEN 2048
#define DEFAULT_RECV_LEN 2048
#define server_addr "192.168.1.10"
FILE *fid, *fdr;
int main(int argc, char *argv[]) {
int iResult, recvbuflen = DEFAULT_RECV_LEN, file_pos = 0;
int bytesRead=0, i=0;
unsigned char sendbuf[DEFAULT_BUFLEN]={NULL}, recvbuf[DEFAULT_RECV_LEN]={NULL};
char filename[256];
WSADATA wsaData;
struct addrinfo *result = NULL,*ptr = NULL,hints;
SOCKET ConnectSocket = INVALID_SOCKET;
int j, iter=0;
unsigned total_bytes_rx = 0,data_tx_cnt = 0,data_tx_pack_cnt=0;
unsigned uiNoBytes2Send = 1024;
unsigned uiNoPackets2Send = 10;
printf("enter file to transfer: \n");
scanf("%s", filename);
printf("Enter number of packets to send (packet size : 1460):");
scanf("%u",&uiNoPackets2Send);
fid=fopen(filename,"rb");
fdr=fopen("D:\\Saravana\\UMA\\DataFiles\\recvfile.bin","wb");
//fclose(fdr);
//fdr=fopen("recvfile.txt","w");
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed: %d\n", iResult);
getch();return 1;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
iResult = getaddrinfo(server_addr, DEFAULT_PORT, &hints, &result);
if (iResult != 0) {
printf("getaddrinfo failed: %d\n", iResult);
WSACleanup();
getch();return 1;
}
ptr=result;
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("Error at socket(): %ld\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
getch();return 1;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
getch();return 1;
}
//bytesRead=fread(&sendbuf[4],1,DEFAULT_BUFLEN,fid);
printf("****** Data Sending Initiated ******\n");
printf("\n **** Sending control packet ****");
sendbuf[0]='c'; sendbuf[1]='t'; sendbuf[2]='r'; sendbuf[3]='l'; //Control string
sendbuf[4] = 0xC2; sendbuf[5] = 0x00; sendbuf[6] = 0x00; sendbuf[7] = 0x00; //SDRAM Address
//#Bytes to transfer
sendbuf[8] = (uiNoPackets2Send&0xFF000000)>>24;
sendbuf[9] = (uiNoPackets2Send&0x00FF0000)>>16;
sendbuf[10] = (uiNoPackets2Send&0x0000FF00)>>8;
sendbuf[11] = (uiNoPackets2Send&0x000000FF);
printf("\n Send buf[11] : %u",sendbuf[11]);
//iResult = send(ConnectSocket, sendbuf, bytesRead+4, 0);
iResult = send(ConnectSocket, sendbuf, DEFAULT_BUFLEN, 0);
if (iResult == SOCKET_ERROR) {
printf("send failed: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
getch();return 1;
}
else
{
printf("\n Control packet sent successfully");
}
printf("\n Starting Data packet transfer ..");
printf("\n");
while(data_tx_pack_cnt<uiNoPackets2Send)
{
bytesRead=fread(&sendbuf[0],1,DEFAULT_BUFLEN,fid);
if(bytesRead<DEFAULT_BUFLEN)
break;
//iResult = send(ConnectSocket, sendbuf, bytesRead+4, 0);
iResult = send(ConnectSocket, sendbuf, DEFAULT_BUFLEN, 0);
if (iResult == SOCKET_ERROR) {
printf("send failed: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
getch();return 1;
}
data_tx_cnt += iResult;
data_tx_pack_cnt++;
printf("\r Current Bytes sent : %u \t Current packet cnt : %u ",iResult,data_tx_pack_cnt);
}
printf("\n Total bytes transferred: %u\n",data_tx_cnt);
strcpy(sendbuf,"term");
iResult = send(ConnectSocket, sendbuf, 1460, 0) ;
if(iResult <0)
{
puts("Send failed\n");
return 1;
}else
printf("\n Control Packet sent to indicate data transfer is complete\n");
if (iResult == SOCKET_ERROR) {
printf("shutdown failed: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
getch();return 1;
}*/
printf("****** Switching to data receive mode ******\n");
//Receive until the server closes the connection
while(1) {
iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
printf("iResult: %d\n",iResult);
if ( iResult > 0 )
{
if ( recvbuf[iResult-5]=='m' && recvbuf[iResult-4]=='s' && recvbuf[iResult-3]=='d' &&
recvbuf[iResult-2]=='p' && recvbuf[iResult-1]=='d')
{
//fwrite(recvbuf,sizeof(char),iResult-5,fdr);
printf("Connection terminated\n");
break;
}
fwrite(recvbuf,sizeof(char),iResult,fdr);
//if(total_bytes_rx%(1024*1024)== 0)
total_bytes_rx +=iResult;
printf("\rBytes received: Global %u \t Local : %u", total_bytes_rx,iResult);
//printf("Bytes received: Local : %u\n",iResult);
//fclose(fdr);
}else{
printf("recv failed: %d\n Closing all Open Sockets\n", WSAGetLastError());
break;
}
} //while( iResult > 0 );
end_pgm:
fclose(fid);
fclose(fdr);
closesocket(ConnectSocket);
WSACleanup();
printf("Total Bytes received: %d\n", total_bytes_rx);
getch();
}