CFile::modeCreate Directs the constructor to create a new file. If the file exists already, it is truncated to 0 length.CFile::modeNoTruncate Combine this value with modeCreate. If the file being created already exists, it is not truncated to 0 length. Thus the file is guaranteed to open, either as a newly created file or as an existing file. This might be useful, for example, when opening a settings file that may or may not exist already. This option applies to CStdioFile as well.CFile::modeRead Opens the file for reading only.CFile::modeReadWrite Opens the file for reading and writing.CFile::modeWrite Opens the file for writing only.CFile::modeNoInherit Prevents the file from being inherited by child processes.CFile::shareDenyNone Opens the file without denying other processes read or write access to the file. Create fails if the file has been opened in compatibility mode by any other process.CFile::shareDenyRead Opens the file and denies other processes read access to the file. Create fails if the file has been opened in compatibility mode or for read access by any other process.CFile::shareDenyWrite Opens the file and denies other processes write access to the file. Create fails if the file has been opened in compatibility mode or for write access by any other process.CFile::shareExclusive Opens the file with exclusive mode, denying other processes both read and write access to the file. Construction fails if the file has been opened in any other mode for read or write access, even by the current process.CFile::shareCompat This flag is not available in 32 bit MFC. This flag maps to CFile::shareExclusive when used in CFile::Open.CFile::typeText Sets text mode with special processing for carriage return–linefeed pairs (used in derived classes only).CFile::typeBinary Sets binary mode (used in derived classes only). CFile::osNoBuffer The system opens a file with no system caching. For more information see FILE_FLAG_NO_BUFFERING in CreateFile in the Platform SDK.CFile::osWriteThrough The system writes through any intermediate cache and goes directly to disk. For more information see FILE_FLAG_WRITE_THROUGH in CreateFile in the Platform SDK.CFile::osRandomAccess A file is accessed randomly. The system can use this as a hint to optimize file caching.CFile::osSequentialScan A file is accessed sequentially from beginning to end. The system can use this as a hint to optimize file caching. For more information see FILE_FLAG_SEQUENTIAL_SCAN in CreateFile in the Platform SDK.
CSFile.Open(TEXT("数据目录.wdf"),CFile::modeRead);
WDK_FILE_HEAD WdfFile; //文件长度 tem2=0xFEB2127; int tem2=SFile->GetLength();
//按以下文件偏移设置文件不能获得数据 汇编下跟踪发现read返回值为0 查msdn发现0 表示文件结尾
//而且文件偏移在0xFEB03EC前读取数据 read都认为0xFEB03EC是文件尾 read返回值就是文件偏移到0xFEB03EC的字节数
SFile->Seek(0xFEB03EC,CFile::begin);
SFile->Read(&WdfFile,sizeof(WDK_FILE_HEAD));
//向后移动4个字节文件指针后 可以正常获得数据 汇编下跟踪返回值正常
SFile->Seek(0xFEB03F0,CFile::begin);
SFile->Read(&WdfFile,sizeof(WDK_FILE_HEAD));
CFile::osNoBuffer The system opens a file with no system caching. For more information see FILE_FLAG_NO_BUFFERING in CreateFile in the Platform SDK.CFile::osWriteThrough The system writes through any intermediate cache and goes directly to disk. For more information see FILE_FLAG_WRITE_THROUGH in CreateFile in the Platform SDK.CFile::osRandomAccess A file is accessed randomly. The system can use this as a hint to optimize file caching.CFile::osSequentialScan A file is accessed sequentially from beginning to end. The system can use this as a hint to optimize file caching. For more information see FILE_FLAG_SEQUENTIAL_SCAN in CreateFile in the Platform SDK.
9楼的兄弟 方法稍微修正下：
CFile::modeRead|CFile::typeBinary