BUG: Select Case Does Not Allow Character Expression String

• Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0 and 1.0a
• Microsoft FORTRAN PowerStation 32 for Windows NT, version 1.0

SYMPTOMS

Compiling a program that contains a SELECT CASE statement that uses a variable in a character substring of length 1, fails and gives the following error message:

   F2868: SELECT CASE : character expression must be of length 1

CAUSE

The compiler incorrectly evaluates the length of a character substring, when the character substring is defined using a variable, not a constant.

RESOLUTION

Avoid a SELECT statement that uses a character substring defined with a variable. Instead, use a character substring defined with a constant. As an alternative, you can define a temporary character variable of length 1 and assign the substring to that variable, which can be later used with a SELECT statement.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Sample Code to Reproduce Problem

C Compile options needed: none C The following program reproduces the problem:

      program go
      character*5 a
      integer*4 len
      a = "Hello"
      len = 1
      select case( a(len:len) )  ! offending statement
             case default
      end select
      end

Sample Code to Solve Problem

C Compile options needed: none C The following code solves the problem:

      program go
      character*5 a
      a = "Hello"
      select case( a(1:1) )
             case default
      end select
      end

Sample Code to Solve Problem

C Compile options needed: none C The following code solves the problem:

      program go
      character a*5,tmp*1
      integer*4 len
      a = "Hello"
      len = 1
      tmp=a(len:len)
      select case( tmp )
             case default
      end select
      end