- 1 year ago
Cross-thread visibility of changes to std::vector synchronized only with Win32 events
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In C++, if you want to synchronize access to a std::vector
across multiple threads and make changes visible between threads using Win32 events, you can follow these steps:
- Define a
std::vector
and aHANDLE
event for synchronization:
cppstd::vector<int> sharedVector;
HANDLE vectorEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);
- Create separate threads that will read and modify the
std::vector
. Ensure that each thread has access to thesharedVector
andvectorEvent
:
cppDWORD WINAPI ReaderThread(LPVOID lpParam) {
while (true) {
WaitForSingleObject(vectorEvent, INFINITE);
// Access sharedVector to read data
// Process the data as needed
}
return 0;
}
DWORD WINAPI WriterThread(LPVOID lpParam) {
while (true) {
// Modify sharedVector
// Signal the event to notify readers
SetEvent(vectorEvent);
}
return 0;
}
- Create and start the reader and writer threads:
cppHANDLE readerThread = CreateThread(nullptr, 0, ReaderThread, nullptr, 0, nullptr);
HANDLE writerThread = CreateThread(nullptr, 0, WriterThread, nullptr, 0, nullptr);
- To clean up resources, remember to close the event and wait for the threads to finish:
cppCloseHandle(vectorEvent);
WaitForSingleObject(readerThread, INFINITE);
WaitForSingleObject(writerThread, INFINITE);
CloseHandle(readerThread);
CloseHandle(writerThread);
This approach uses a Win32 event (vectorEvent
) to synchronize access to the std::vector
(sharedVector
). The writer thread modifies the vector and signals the event to notify the reader thread. The reader thread waits for the event to be signaled and then accesses and processes the data in the vector.
Remember to handle synchronization and thread safety properly to avoid race conditions or other concurrency issues when accessing the shared data structure.