FIX: Project Deletes Precompiled Header Created by Other Project

ID: Q194615

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions, version 6.0

SYMPTOMS

If one project uses a pre-compiled header (using compiler option /Yu) that was created by another project, then the pre-compiled header is deleted when you perform a Clean or Rebuild-All command in Developer Studio.

RESOLUTION

In the workarounds that follow, a YC project refers to the project that creates the pre-compiled header (PCH); a YU project refers to a project that uses, but does not create, the pre-compiled header.

Option 1

Use a custom build step to create the PCH file. This does not impact the YU projects.

In this case you can modify Project Settings for the Stdafx.cpp file so that it is built with custom build rules rather than the standard method for building the PCH file.

To do this from the YC project:

On the Project menu, click Settings to bring up the Project Settings dialog box.

From the tree view in the left window, select Stdafx.cpp in the Source Files folder.

Click the General tab in the right window and select Always use custom build step.

Click the Custom Build tab.

In the Commands window, enter the following (where Yc.pch is the name of your project pre-compiled header file):


   attrib -r $(OutDir)\yc.pch
   cl [compiler switches] /Yc"stdafx.h" stdafx.cpp
   attrib +r $(OutDir)\yc.pch

In the Outputs window, enter the following (where Yc.pch is the name of your project pre-compiled header file):
```
   $(OutDir)\yc.pch
   $(OutDir)\stdafx.obj 
```

Click Dependencies. Type the following in the user-defined Dependencies window:
```
   stdafx.h 
```

Click OK.

NOTES:

You get the following error at the beginning of your Rebuild-All or Clean:

Error: Could not delete file "filename" : Access is denied.

The pre-compiled header is not deleted even in the YC project when a Clean or Rebuild-All command is executed in Developer Studio. This behavior is consistent with Microsoft Visual C++, version 5.0.

Option 2

Use an environment variable to set the PCH switch in the YU projects. This does not impact the YC project(s).

In the Windows NT Setting, Control Panel applet, select the System icon. Then select the Environment tab.

In the Variable field, type in YCREL.

In the Value field, enter:
```
   /Fp"..\Release/yc.pch" /Yu"stdafx.h" 
```
(This uses relative paths although it is not required). Note that you also need an environment variable for the debug build, such as YCDBG. That is, you need two environment variables for each project that produces PCH files.

NOTE: In Windows 95 or Windows 98, you must make system-wide environment variable setting changes by adding appropriate MS-DOS SET commands to the Autoexec.bat file and rebooting.

In the Project Settings dialog box for the YU project, select the main node of the project labeled YU in the file tree.

In the C/C++ tab, select the Precompiled Headers category.

Click Not using precompiled headers. This turns off the /Fp and /Yu compiler switches.

In the Project Options window (at the bottom of the Project Settings dialog box) add $(YCDBG) for your debug build or $(YCREL) for the Release build.

Click OK.

If you have not restarted Developer Studio since setting the environment variables, you must close it and reopen it.

NOTES:

You can unintentionally delete or modify the environment settings.

Build settings are hidden, which may make trouble-shooting build-related problems more difficult.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

MORE INFORMATION

Steps to Reproduce Behavior

Create two MFC AppWizard DLL projects in the same workspace.

Switch to the Win32 Release configuration for each project.

In Project2, delete the Stdafx.cpp file from the project.

In Project2, in the Project Settings dialog box, change the /Fp option to point to the PCH file from Project1.

Build Project1.

Build Project2.

Rebuild All Project2 only.

RESULT:

fatal error C1083: Cannot open precompiled header file: 'filename': No such file or directory

Additional query words:

Keywords : kberrmsg kbservicepack kbide kbVC600bug kbVS600sp2 kbVS600SP1 kbVS600sp3fix
Version : winnt:6.0
Platform : winnt
Issue type : kbbug