//获取当前操作系统的分配粒度
SYSTEM_INFO sinf;
GetSystemInfo(&sinf);
DWORD dwAllocationGranularity = sinf.dwAllocationGranularity;
//GENERIC_WRITE | GENERIC_READ, FILE_SHARE_READ这两个参数如果设置错误将导致错误
HANDLE hFile = CreateFile("join", GENERIC_WRITE | GENERIC_READ, FILE_SHARE_READ,
NULL, CREATE_ALWAYS, FILE_FLAG_SEQUENTIAL_SCAN, NULL);
//PAGE_READWRITE这个属性必须和GENERIC_WRITE | GENERIC_READ属性对应
HANDLE hFileMapping = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0,
0x4000000, NULL);
CloseHandle(hFile);
__int64 qwFileSize = 0x4000000;
__int64 qwFileOffset = 0;
__int64 T = 600 * sinf.dwAllocationGranularity;
DWORD dwBytesInBlock = 1000 * sinf.dwAllocationGranularity;
//qwFileOffset>>32 取６４位高位
//qwFileOffset&0xFFFFFFFF 取６４位低位
//FILE_MAP_ALL_ACCESS这个属性与CreateFile和CreateFileMapping属性必须匹配
PBYTE pbFile = (PBYTE)MapViewOfFile(hFileMapping, FILE_MAP_ALL_ACCESS,
(DWORD)(qwFileOffset>>32), (DWORD)(qwFileOffset&0xFFFFFFFF), dwBytesInBlock);
memcpy(pbFile, "123", 3);
char temp[3];
memcpy(temp, pbFile, 3);
UnmapViewOfFile(pbFile);