HOWTO: Test for End of File with CFile and CStdioFile

• The Microsoft Foundation Classes (MFC), used with:
  • Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
  • Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 2.2, 4.0

SUMMARY

The Microsoft Foundation Classes (MFC) provide a CFileException class. The CFileException class includes public data members that contain operating- system errors and C Run-time errors that may be generated by certain file operations.

MORE INFORMATION

The CFile and CStdioFile classes may throw a CFileException when certain error conditions occur; however, these classes do not throw a CFileException when the end of file is reached. If an application using the CFile or CStdioFile class needs to check for the end-of-file condition when reading from a file, the return values from the Read() and ReadString() member functions should be checked.

CFile::Read returns the actual number of bytes read. If this number is less than the bytes requested, then the end of file has been reached.

CStdioFile::ReadString returns a NULL pointer when the end of file has been reached.

Additional query words: EOF TRY CATCH

Keywords : kbFileIO kbMFC kbVC100 kbVC150 kbVC200 kbVC400 kbGrpMFCATL
Version : winnt:1.0,2.0,2.1,2.2,4.0
Platform : winnt
Issue type : kbhowto