创建和打开内存映射

class MemoryShare
{
public:static HANDLE CreateMemoryMap(std::string id, size_t shared_mem, void* &map_buf){return MemoryShare::CreateMemoryMap(id, shared_mem, "", map_buf);}static HANDLE CreateMemoryMap(std::string id, size_t shared_mem, std::string file, void* &map_buf){HANDLE hFile = NULL;HANDLE hMap = NULL;if (!file.empty())hFile = CreateFileA(file.c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);if (hFile){hMap = CreateFileMappingA(hFile, NULL, PAGE_READWRITE, 0, shared_mem, id.c_str());}else{hMap = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, shared_mem, id.c_str());}if (hMap == NULL){if (hFile)CloseHandle(hFile);return false;}map_buf = MapViewOfFile(hMap, FILE_MAP_ALL_ACCESS, 0, 0, 0);if (!map_buf){if (hFile)CloseHandle(hFile);CloseHandle(hMap);hMap = NULL;return false;}if (hFile)CloseHandle(hFile);return hMap;}static bool OpenMemoryMap(std::string id, size_t map_size,void* &map_buf){HANDLE hMap = OpenFileMappingA(FILE_MAP_ALL_ACCESS, 0, id.c_str());if (!hMap){return false;}map_buf = MapViewOfFile(hMap, FILE_MAP_ALL_ACCESS, 0, 0, map_size);if (!map_buf){CloseHandle(hMap);return false;}CloseHandle(hMap);return true;}static void CloseMemoryMap(void* base_map){if (base_map)UnmapViewOfFile(base_map);}};

Example

void* pto = NULL;
HANDLE hMem = MemoryShare::CreateMemoryMap("yoohoo", 3000, "G:/a.txt", pto);
if (hMem)
{memcpy(pto, "123456789", 10);
}void* pmap = NULL;if (MemoryShare::OpenMemoryMap("yoohoo", 256, pmap))
{cout << (char*)pmap;
}getchar();
if (hMem)CloseHandle(hMem);
MemoryShare::CloseMemoryMap(pmap);