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# BUG: R6000 After Many Calls to RunQQ If Linked with Defaults

Article ID: 123730

Article Last Modified on 10/2/2003

APPLIES TO

- Microsoft FORTRAN PowerStation 1.0 Standard Edition
- Microsoft Fortran PowerStation 1.0a for MS-DOS

This article was previously published under Q123730

## SYMPTOMS

RunQQ fails and returns error R6000 (stack overflow) after being called many times. The failure occurs after less than 100 calls (the exact number depends on things like system memory) given the following conditions:

- Stack checking is turned on when compiling the task called from RunQQ.
- The application was linked using the default stack size of 1MB 'reserve' and 4K 'commit'.
- The application is run from MS-DOS.

## RESOLUTION

Set the linker stack option to 32K 'reserve' and 4K 'commit'. This is the default when compiling and linking using FL32 on the command line.

## STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.
This problem does not occur with FORTRAN PowerStation 32.

## MORE INFORMATION

Page 168 of the User's Guide states that the default stack for the linker is 1MB 'reserve' and 4K 'commit'. It also states that this is 0x1000000 and 0x4000 respectively - which is inconsitent, it is actually 0x100000 (1MB) and 0x1000 (4K). These are the values used by default in the Visual Workbench. Applications built this way will fail as described above.
The default stack used when building from the command line with FL32 is 32K 'reserve' and 4K 'commit'. When an application is compiled and linked using the default options of FL32, it does not have the problem described above.
To demonstrate the problem, build both sample programs using the linker's default options in the Visual Workbench. The only compile option required is /Ge for TASK.FOR. Then exit Windows and run TEST.EXE from MS-DOS.
To demonstrate the problem without using the Visual Workbench, use the following commands (assuming the maintenance release is installed). The linker version for the maintenance release is 1.0F.

FL32 /c /Ge test.for task.for
LINK test.obj libf.lib libc.lib
BINDMSF test.exe
LINK task.obj libf.lib libc.lib

NOTE: It is not necessary to apply BINDMSF to the TASK.EXE because it is being run from TEST.EXE, which will have already loaded the MS-DOS extender. Feel free to use BINDMSF on TASK.EXE; it will have no effect on this test.

### Sample Code TEST.FOR

    C Compile options required: none or /Ge (it will not affect the test)

          include 'flib.fi'
          include 'flib.fd'

          character*1 answer
          integer*4 i
          integer*4 r

          do i=1,100

              write(*,*)"ready to runqq task.exe"
              r = runqq("task.exe","/none")
              if (r .ne. 0) then
                  write(*,*)i," task.exe failed"
                  read(*,FMT='(a1)') answer
              else
                  write(*,*)i," task.exe was successful"
              end if

          end do

          end

### SAMPLE CODE task.for

    C Compile options required: /Ge (must turn on stack checking for TASK)

          write(*,*)"control passed to task.exe"
          end

Additional query words: nofpsnt 1.00 1.00a docerr

Keywords: KB123730