Q100376: FIX: Intrinsic REAL Function Assigned to COMPLEX Fails

Article: Q100376
Product(s): Microsoft Fortran Compiler
Version(s): 1.0
Operating System(s): 
Keyword(s): 
Last Modified: 24-MAR-2000

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The information in this article applies to:

- Microsoft FORTRAN PowerStation for MS-DOS, version 1.0 
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SYMPTOMS
========

An application that assigns the result of a REAL intrinsic function to a COMPLEX
variable may generate incorrect results.

CAUSE
=====

The compiler generates incorrect code to perform this assignment.

RESOLUTION
==========

There are two methods to avoid this problem, as follows:

- Modify the source code to assign the result of the REAL function to a
  temporary REAL variable. Then specify the temporary variable in the
  assignment statement.

- Add zero to the result of the function.

STATUS
======

Microsoft has confirmed this to be a problem in FORTRAN PowerStation version 1.0
for MS-DOS. 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" (without the
quotation marks) 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
================

Specifying different compiler options does not correct this problem. The various
options only change the incorrect value that the code places in the COMPLEX
variable.

The following sample code demonstrates this problem:

Sample Code #1
--------------

  c Compile options needed: None

        complex*8 c
        real*4 x
        x = 1.0
        c = exp(x)
        print *, 'complex c1 = exp(x); c = ', c
        end


The following sample code demonstrates one method to work around this problem:

Sample Code #2
--------------

  c Compile options needed: None

        complex*8 c
        real*4 x, tmp
        x = 1.0
        tmp = exp(x)
        c = tmp
        print *, 'complex c1 = exp(x); c = ', c
        end

The following sample code demonstrates another method to work around this
problem:

Sample Code #3
--------------

  c Compile options needed: None

        complex*8 c
        real*4 x
        x = 1.0
        c = exp(x) + 0
        print *, 'complex c1 = exp(x); c = ', c
        end

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

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Keywords          :  
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword3 kbFORTRANPower100DOS
Version           : :1.0
Issue type        : kbbug
Solution Type     : kbfix

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