DOCUMENT:Q118547  04-MAY-2001  [fortran]
TITLE   :PRB: Multithreaded Program Crashes
PRODUCT :Microsoft Fortran Compiler
PROD/VER::1.0
OPER/SYS:
KEYWORDS:kbcode kbCompiler kbFL32 kbFortranPS

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Fortran Powerstation 32 for Windows NT, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

A program that uses the multithread run-time library fails to run to completion
or generates a Dr. Watson access-violation error message.

CAUSE
=====

This behavior can occur if the compile options are not consistent with the
libraries included in linking.

RESOLUTION
==========

If the program is linked using the MSFRT.LIB and MSVCRT.LIB files, your object
modules must be compiled using the -MD option.

NOTE: This behavior was changed in Microsoft FORTRAN PowerStation version 4.0.

MORE INFORMATION
================

To demonstrate the problem and workaround, compile the sample code below
(TESTC), using the four different tests listed. The first two tests demonstrate
the problem, while the last two tests show two sets of options that do not cause
problems:

Test 1
------

The TESTC created using these options will produce a Dr. Watson error message:

      CL -c TESTC.CPP
      FL32 -LD TESTF.FOR
      FL32 -MD TESTC.OBJ TESTF.LIB

Test 2
------

The TESTC created using these options will not produce an error message, but will
fail to run completely and will not produce any output:

      CL -c -MD TESTC.CPP
      FL32 -LD TESTF.FOR
      FL32 -ML TESTC.OBJ TESTF.LIB

-or-

      FL32 -MT TESTC.OBJ TESTF.LIB

Test 3
------

The TESTC created using these options will create a TESTC program that is linked
to MSFRT.LIB and MSVCCRT.LIB. The actual run-time code is in the DLLs MSFRT10
and MSVCRT10. This TESTC will correctly display the message, "Factorial of 7 is:
5040":

      CL -c -MD TESTC.CPP
      FL32 -LD TESTF.FOR
      FL32 -MD TESTC.OBJ TESTF.LIB

Test 4
------

The TESTC created using these options has the run-time code statically linked
into the executable file. It will also correctly display the message, "Factorial
of 7 is: 5040":

      CL -c TESTC.CPP
      FL32 -LD TESTF.FOR
      FL32 -ML TESTC.OBJ TESTF.LIB

-or-

      FL32 -MT TESTC.OBJ TESTF.LIB

C Sample Code
-------------

   /* Compile options needed: see text above
   */ 
      #include <iostream.h>
      extern "C" {void __stdcall FACT (int n, int *amt);}
      int main() {
         int amt;
         FACT(7, &amt);
         cout << "Factorial of 7 is: " << amt;
         return 0;
      }

FORTRAN Sample Code
-------------------

   C Compile options needed: see text above
         SUBROUTINE Fact[DLLEXPORT](n, amt)
         INTEGER*4 n [VALUE]
         INTEGER*4 amt [REFERENCE]
         INTEGER*4 i
         amt = 1
         DO i = 1, n
           amt = amt * i
         END DO
         END

Additional query words: 1.00 multi-thread

======================================================================
Keywords          : kbcode kbCompiler kbFL32 kbFortranPS 
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword2 kbFORTRANPower32100NT
Version           : :1.0

=============================================================================

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