вы можете использовать std::weak_ptr там, чтобы отслеживать вещи, которые вышли из области видимости в другом потоке.
У меня нет простого примера на этот счет.не так просто:
https://github.com/alexeyneu/bitcoin/commit/bbd5aa3e36cf303779d888764e1ebb3bd2242a4a
ключевые строки на этом:
std::weak_ptr<int> com_r;
...
bhr->SetProgressValue(hwnd , com_r.expired() == 0 ? reserve = *com_r.lock() : reserve, 190);
и
extern std::weak_ptr<int> com_r;
...
//inside a class
std::shared_ptr<int> sp_tray;
com_r = sp_tray;
*sp_tray = nVerificationProgress*190;
и это тестовый пример (обновлено)
#include "stdafx.h"
#include "bay.h"
#include <condition_variable>
#include <thread>
#include <atomic>
#include <memory>
#include <sstream>
#include <string>
#include <vector>
#include <iostream>
#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst; // current instance
wchar_t szTitle[MAX_LOADSTRING]; // The title bar text
wchar_t szWindowClass[MAX_LOADSTRING]; // the main window class name
// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPTSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: Place code here.
MSG msg;
HACCEL hAccelTable;
// Initialize global strings
LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadString(hInstance, IDC_BAY, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_BAY));
// Main message loop:
while (GetMessage(&msg, NULL, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_BAY));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = MAKEINTRESOURCE(IDC_BAY);
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassEx(&wcex);
}
HWND hWnd;
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance; // Store instance handle in our global variable
hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
std::thread u,u2;
UINT CALLBACK hammer(VOID *c);
UINT CALLBACK hammersmith(VOID *c);
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
HDC hdc;
switch (message)
{
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_EXIT:
break;
case IDM_LETSGO:
u = std::thread(&hammer,(LPVOID)NULL);
u2 = std::thread(&hammersmith,(LPVOID)NULL);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
break;
case WM_CLOSE:
DefWindowProc(hWnd, message, wParam, lParam);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
std::shared_ptr<int> sp_tray;
std::weak_ptr<int> com_r;
std::mutex com_m;
UINT CALLBACK hammer(VOID *c)
{
int reserve = 0;
AllocConsole();
freopen("CON", "w", stdout);
while (1)
{
std::unique_lock<std::mutex> lb(com_m);
reserve = com_r.expired() == 0 ? *com_r.lock(): 5;
lb.unlock();
std::cout << reserve;
}
return 0;
}
UINT CALLBACK hammersmith(VOID *c)
{
while (1)
{
std::unique_lock<std::mutex> lb(com_m);
sp_tray = std::shared_ptr<int>(new int(7));
com_r = sp_tray;
lb.unlock();
sp_tray.reset();
}
return 0;
}