PRB: Build Errors Using Precompiled Header in Debugging Lib

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 1.0, 2.0, 2.1, 2.2,

       4.0, 4.1, 5.0
  

SYMPTOMS

An attempt to create a debugging library that uses precompiled headers may fail and fatal build errors may be generated. With the 16-bit edition, the CVPACK and LINK utilities may generate the following messages:

   CVPACK : fatal error CK1017: cannot find precompiled types file;
            relink with file.obj
   LINK : warning LNK4027: CVPACK error

   LINK : fatal error LNK1211: precompiled type information not found;
   "<filename>" not linked or overwritten

CAUSE

When you specify the /Yc and /Z7 options on the compiler command line, Microsoft C/C++ generates a precompiled header file that contains CodeView debugging information. The error occurs only when you store the precompiled header in a library, use the library to build an object module, and the source code does not refer to any of the functions the precompiled header file defines.

RESOLUTION

There are two methods to work around this situation, as follows:

• Specify the /Yd compiler option switch to add the CodeView information from the precompiled header to each object module. This method is less desirable because it generally produces large object modules that can increase the time required to link the application.
• NOTE: The following work-around is for 32-bit versions only. Specify the /Yl<symbol> compiler option switch, where <symbol> is the name of an arbitrary symbol in the library, when you create a precompiled header file that does not contain any function definitions. This switch directs the compiler to store the debugging information in the precompiled header file.

MORE INFORMATION

When you compile a module with the /Yc and /Yl<symbol_name> option switches using the 32-bit edition, the compiler creates a symbol similar to __@@_PchSym_@00@...@<symbol_name>, where the ellipsis (...) represents a linker generated character string, and stores it in the object module. Any source file that you compile with this precompiled header refers to the specified symbol, which causes the linker to include the object module and its debugging information from the library.

The following code example demonstrates the problem.

Sample Code

/*
 * To demonstrate this problem, perform the following five steps:
 *
 * 1. Compile TEST1.C as follows: cl /Yctest.h /Z7 /c TEST1.C
 * 2. Compile TEST2.C as follows: cl /Yutest.h /Z7 /c TEST2.C
 * 3. Build a library that contains TEST1.OBJ and TEST2.OBJ as
 *    follows: lib /out:test.lib test1.obj test2.obj
 * 4. Compile TEST3.C as follows: cl /Yutest.h /Z7 /c TEST3.C
 * 5. Link the application as follows:
 *       link /debugtype:cv /debug:notmapped,full test3.obj test.lib
 *
 * To correct this problem, do one of the following:
 *
 *   1. 32-bit only)  Compile TEST1.C in step 1 as follows:
 *        cl /Yctest.h /YlAnyName /Z7 /c TEST1.C
 *      Then, repeat step 2 through 5.
 *
 *   2. Repeat steps 1 through 5, adding the /Yd command line option
 *      to steps 1, 2, and 4.
 */

TEST.H

   #include <stdio.h>

TEST1.C

   #include "test.h"

TEST2.C

   #include "test.h"

   void test2func(void)
   {
      printf("inside TEST2FUNC...\n");
   }

TEST3.C

   #include "test.h"

   void test2func(void);

   void main(void)
   {
      printf("inside MAIN...\n");
   }