内存映射

来源:互联网 发布:海洋cms一点不好用 编辑:程序博客网 时间:2024/05/18 23:27

内存映射:

HANDLE CreateFileMapping(Handle 文件,PSECURITY_ATTRIBUTES 安全属性,DWORD 保护属性,DWORD 文件大小高32位,DWORD 文件大小低32位,PCTSTR 映射名称)

PVOID MAPViewOfFile(HANDLE 映射对象,DWORD访问属性,DWORD 偏移量高32位,DWORD 偏移量低32位,SIZE_T 字节数)

//调用的时候传入地址就可以,测试用的txt文件

void Mapping(LPCTSTR path) {     HANDLE fFile01 = (HANDLE) CreateFile(path, GENERIC_WRITE | GENERIC_READ, 0, NULL,CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);    char chBuffer[256];    memcpy(chBuffer, "testing", 7);    DWORD dwWritenSize = 0;    BOOL bRet = WriteFile(hFile01, chBuffer, 7, &dwWritenSize, NULL);    CloseHandle(hFile01);    HANDLE hFile = CreateFile(path, GENERIC_WRITE | GENERIC_READ, 0, NULL,OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);    DWORD dwFileSize = GetFileSize(hFile, NULL);    //创建一个内存映射文件,大小为打开文件大小    HANDLE hFileMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0,dwFileSize , NULL);    //预定一块地址空间区域,并可以通过指针访问    PVOID pvFile = MapViewOfFile(hFileMap, FILE_MAP_WRITE, 0, 0, 0);    PSTR pch = (PSTR)pvFile;    //小写变大写    strupr(pch);    cout << pch << endl;    //从进程空间撤销对文件数据的关联    UnmapViewOfFile(pvFile);    CloseHandle(hFileMap);    SetFilePointer(hFile, dwFileSize, NULL, FILE_BEGIN);    SetEndOfFile(hFile);    CloseHandle(hFile);}
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