PRB: "Access to an Unnamed File Was Denied" Error

Last reviewed: March 4, 1998
Article ID: Q181880

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions, versions 4.0, 5.0

SYMPTOMS

You get the following error when calling CFile::Read():

   Access to an unnamed file was denied.

If run under the Microsoft Visual C++ debugger, you will see the following error:

   CFile exception: accessDenied, File Unknown, OS error information = 5

CAUSE

You are actually opening the file without read access. The following intuitively correct code causes the error:

   CFile cf;
   int data;

   cf.Open("myfile.dat", CFile::modeRead | CFile::modeWrite);

   cf.Write(&data, sizeof(int));

   cf.Read(&data, sizeof(int));

RESOLUTION

Specify CFile::modeReadWrite instead of the logical OR of CFile::modeRead and CFile::modeWrite.

STATUS

This behavior is by design.

REFERENCES

For more information about CFile, or other MFC classes, consult the Microsoft Visual C++ online help.

Keywords          : CodeGen kberrmsg
Version           : WINNT:4.0,5.0
Platform          : winnt
Issue type        : kbprb

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Last reviewed: March 4, 1998
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