dll — код C ++ в DLL_PROCESS_DETACH в DllMain не выполняется

у меня есть client и server написанный на C ++. client в dll и server в .exe, Я сначала начинаю server а затем ввести dll в explorer.exe с client в этом. Когда я начинаю client и отправить сообщение в DLL_PROCESS_ATTACH то работает нормально и client а также server общаемся.

Но когда я перезапускаю explorer.exe и dll выгружен означает, что DLL_PROCESS_DETACH должен называться таким образом, означая, что когда я начинаю client и отправить сообщение server от DLL_PROCESS_DETACH тогда это также должно работать, но это не так. Я работаю на машине с Windows 10 и VS2015.

Вот мой код

client.cpp

#define _CRT_SECURE_NO_WARNINGS
#define WIN32_LEAN_AND_MEAN

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <tchar.h>
#include <windows.h>
#include <conio.h>
#include <winsock2.h>
#include <ws2tcpip.h>// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

using namespace std;

//==================================================================================================================
int SendMessageToServer();
//==================================================================================================================

INT APIENTRY DllMain(HMODULE hModule, DWORD dwReason, LPVOID lpReserved) {
switch (dwReason) {
case DLL_PROCESS_ATTACH:
//Send message to server that the dll is about to be unloaded
//works when being called from here
//SendMessageToServer();
break;
case DLL_PROCESS_DETACH:
//Send message to server that the dll is about to be unloaded
//doesn't work when being called from here
SendMessageToServer();

break;

}

return true;
}//=====================================================================================================================
int SendMessageToServer() {
WSADATA wsaData;
SOCKET ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
char *sendbuf = "this is a test";
char recvbuf[DEFAULT_BUFLEN];
int iResult;
int recvbuflen = DEFAULT_BUFLEN;

// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}

ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;char* hostname = new char[sizeof(char*) + 1];
hostname = "192.168.178.17";
// Resolve the server address and port
iResult = getaddrinfo(hostname, DEFAULT_PORT, &hints, &result);
if (iResult != 0) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}

// Attempt to connect to an address until one succeeds
for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {

// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}

// Connect to server.
iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}

freeaddrinfo(result);

if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
return 1;
}

// Send an initial buffer
iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);
if (iResult == SOCKET_ERROR) {
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
return 1;
}

printf("Bytes Sent: %ld\n", iResult);

// shutdown the connection since no more data will be sent
iResult = shutdown(ConnectSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
return 1;
}

// Receive until the peer closes the connection
do {

iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
if (iResult > 0)
printf("Bytes received: %d\n", iResult);
else if (iResult == 0)
printf("Connection closed\n");
else
printf("recv failed with error: %d\n", WSAGetLastError());

} while (iResult > 0);// cleanup
closesocket(ConnectSocket);
WSACleanup();

system("PAUSE");
return 0;
}
//==================================================================================================================

сервер

server.cpp

#undef UNICODE

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

// Need to link with Ws2_32.lib
#pragma comment (lib, "Ws2_32.lib")
// #pragma comment (lib, "Mswsock.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"
int __cdecl main(void)
{
WSADATA wsaData;
int iResult;

SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;

struct addrinfo *result = NULL;
struct addrinfo hints;

int iSendResult;
char recvbuf[DEFAULT_BUFLEN];
int recvbuflen = DEFAULT_BUFLEN;

// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}

ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;

// Resolve the server address and port
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if (iResult != 0) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}

// Create a SOCKET for connecting to server
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}

// Setup the TCP listening socket
iResult = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (iResult == SOCKET_ERROR) {
printf("bind failed with error: %d\n", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1;
}

freeaddrinfo(result);

iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR) {
printf("listen failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}

// Accept a client socket
ClientSocket = accept(ListenSocket, NULL, NULL);
if (ClientSocket == INVALID_SOCKET) {
printf("accept failed with error: %d\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}

// No longer need server socket
closesocket(ListenSocket);

// Receive until the peer shuts down the connection
do {

iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
if (iResult > 0) {
printf("Bytes received: %d\n", iResult);

// Echo the buffer back to the sender
iSendResult = send(ClientSocket, recvbuf, iResult, 0);
if (iSendResult == SOCKET_ERROR) {
printf("send failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
printf("Bytes sent: %d\n", iSendResult);
}
else if (iResult == 0)
printf("Connection closing...\n");
else {
printf("recv failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}

} while (iResult > 0);// shutdown the connection since we're done
iResult = shutdown(ClientSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
printf("shutdown failed with error: %d\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}

// cleanup
closesocket(ClientSocket);
WSACleanup();

system("PAUSE");

return 0;
}