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Microsoft KB Archive/105932

From BetaArchive Wiki

Article ID: 105932

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 Q105932

SYMPTOMS

Character string concatenations that involve the automatic creation of temporary variables may cause the following memory related run-time problems:

  • Very slow execution of the application
  • F6700
  • DX2010


RESOLUTION

This memory loss can be avoided by assigning the concatenated strings to a temporary character string variable.

STATUS

Microsoft has confirmed this to be a problem in FORTRAN PowerStation version 1.0. This problem has been resolved with FORTRAN PowerStation maintenance release version 1.0a for MS-DOS.

FORTRAN PowerStation version 1.0 can be differentiated from the maintenance release version 1.0a by invoking the linker. Typing "link32 | more" from \F32\BIN directory will show version 2.8 for FORTRAN PowerStation version 1.0, and it will show version 1.0f for the maintenance release version 1.0a.

MORE INFORMATION

The following two sample programs demonstrate a memory loss due to string concatenation in the argument list. In both of the following examples, using a temporary variable for the concatenated strings avoids the memory leak.

Sample Code 1

C Compile options needed: none
      character*40 c1,c2
      c1 = 'abcd'
      c2 = 'efgh'
      k = 0
      do i=1,500000
        if(c1//c2 .eq. 'Never') k = k + 1
      end do
      end
                

The code above will run very slowly, and eventually generate:

run-time error F6700
- heap space limit exceeded

Sample Code 2

C Compile options needed: none
      character fmtout*20,label(1,3)*(9)
      double precision value
      data (label(1,j),j=1,3)/' Label',' Output',' Test'/ 
      data value/3.14159/ 
      fmtout='f10.3'
      write(6,'(3a,''='','//fmtout//')')(label(1,j),j=1,3),value
      end
                

The above code on execution will generate:

DOSXMSF : error DX2010: invalid pointer passed to free or realloc : 0005F0F8h.
DOSXMSF : error DX2010: invalid pointer passed to free or realloc : 0005F0F8h.
Label Output Test = 3.142

The code does run to completion because this type of DOS-extender error is not fatal.


Additional query words: 1.00 buglist1.00 fixlist1.00a

Keywords: kbbug kbfix KB105932