PRB: Multithreaded Program Crashes

• Microsoft FORTRAN PowerStation 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