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◄CArchive►                                    ◄Up► ◄Contents► ◄Index► ◄Back►
──Microsoft Foundation Classes──────────────────────────────────────────────
 
  CArchive( CFile* pFile, UINT nMode, int nBufSize = 512,
            void FAR* lpBuf = NULL )
  throw( CMemoryException, CArchiveException, CFileException );
 
  Parameter   Description
 
  <pFile>     A pointer to the CFile object that is the ultimate source or
              destination of the persistent data.
 
  <nMode>     A flag that specifies whether objects will be loaded from or
              stored to the archive. The <nMode> parameter must have one
              of the following values:
 
              Value             Meaning
 
              CArchive::load    Load data from the archive. Requires only
                                CFile read permission.
 
              CArchive::store   Save data to the archive. Requires CFile
                                write permission.
 
  <nBufSize>  An integer that specifies the size of the internal file
              buffer, in bytes.
 
              NOTE: The default buffer size is 512 bytes. If you routinely
                    archive large objects, you will improve performance if
                    you use a larger buffer size that is a multiple of the
                    file buffer size.
 
  <lpBuf>     An optional FAR pointer to a user-supplied buffer of size
              <nBufSize>. If you do not specify this parameter, the
              archive allocates a buffer from the local heap and frees it
              when the object is destroyed. The archive does not free a
              user-supplied buffer.
 
  Remarks
 
  Constructs a CArchive object and specifies whether it will be used for
  loading or storing objects. You cannot change this specification after
  you have created the archive.
 
  You may not use CFile operations to alter the state of the file until
  you have closed the archive. Any such operation will damage the
  integrity of the archive. You may access the position of the file
  pointer at any time during serialization by (1) obtaining the archive's
  file object from the GetFile member function and then (2) using the
  ◄CFile::GetPosition► function. You should call CArchive::Flush before
  obtaining the position of the file pointer.
 
  Example
 
  extern char* pFileName;
  CFile f;
  char buf[512];
  if( !f.Open( pFileName, CFile::modeCreate | CFile::modeWrite ) ) {
     #ifdef _DEBUG
        afxDump << "Unable to open file" << "\n";
        exit( 1 );
     #endif
  }
  CArchive ar( &f, CArchive::store, 512, buf );
 
 
  See Also
 
  ◄CArchive::Close►, ◄CArchive::Flush►, ◄CFile::Close►
 
 
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