FIX: C4713: reg86.c, line 4479, 4600

The information in this article applies to:

• The Microsoft C/C++ Compiler (CL.EXE), included with:

      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, version 1.0
  

SYMPTOMS

The compiler generates the following internal compiler error message when the sample program below is compiled with /Oez or /Oxz.

   warning C4713: func: internal compiler error; restarting
      (compiler file '@(#)reg86.c:1.26', line 4600)

   warning C4713: func: INTERNAL COMPILER ERROR; restarting
      (compiler file '@(#)reg86.c:1.26', line 4479)
      Contact Microsoft Product Support Services

NOTE: Global register allocation is included with the /Ox compiler option.

RESOLUTION

The C4713 message is just a warning. The compiler realizes a problem has occurred because of the global register allocation optimization and restarts the compile without the optimization.

To avoid the message, either:

• Use the fast compiler (/f) instead of using the optimizing compiler

  -or-

• Disable the global register allocation optimization or the maximum loop optimization. This can be done by not using the /Oz, /Oe, or /Ox options on the command line or by using #pragma optimize to disable these optimizations in the source file. The comments in the sample code (in the "MORE INFORMATION" section, below) explain how to use the #pragma to work around the problem.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed above. This is not a problem in Visual C++, 32-bit Edition. This problem was corrected in Visual C++ version 1.5.

MORE INFORMATION

The following sample code can be used to demonstrate this problem:

Sample Code

/* Compile options needed: /c /f- /Oez
*/
      // Uncomment for work around
      // #pragma optimize ("e", off)

      typedef struct tagRecord
      {
          long lField1;
          long lField2;
      } Record;
      typedef Record _far * LPRecord;

      long _far _pascal func1 (void _far *);
      long _far func2(unsigned, void _far *, LPRecord, void _far *, long);

      long dwSmag;

      unsigned _far func(
          unsigned nParam1,
          LPRecord lpParam2,
          LPRecord lpParam3,
          void _far * lpParam4,
          long lParam5)
      {

          if (func1 (lpParam3))
              goto error;

          if (lpParam4 == 0)
              lpParam4 = (char _far *)lpParam3
                  + lpParam3->lField1
                  + lpParam3->lField2;

          if (lParam5 == -1)
              lParam5 = func1 (&dwSmag);

          func2 (
              nParam1,
              (char _far *)lpParam2
                  + lpParam2->lField1
                  + lpParam2->lField2,
              lpParam3,
              lpParam4,
              lParam5
              );

      error:
          return 0;
      }

      // Uncomment for work around
      // #pragma optimize ("", on)