Microsoft KB Archive/50401

Knowledge Base

Example of Using EXTERNAL for User-Defined Function

Article ID: 50401

Article Last Modified on 12/1/2003

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APPLIES TO

• Microsoft FORTRAN Compiler 4.0
• Microsoft FORTRAN Compiler 4.01
• Microsoft FORTRAN Compiler 4.1
• Microsoft FORTRAN Compiler 5.0
• Microsoft FORTRAN Compiler 5.1
• Microsoft FORTRAN Compiler 4.1
• Microsoft FORTRAN Compiler 5.0
• Microsoft FORTRAN Compiler 5.1
• Microsoft FORTRAN PowerStation 1.0 Standard Edition
• Microsoft Fortran PowerStation 1.0a for MS-DOS
• Microsoft FORTRAN PowerStation 32
• Microsoft FORTRAN PowerStation 32

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This article was previously published under Q50401

SUMMARY

In a FORTRAN application, the EXTERNAL statement specifies that a user-defined name is a subroutine or function that can be used as a formal argument. In addition, an application can use the EXTERNAL statement to replace an intrinsic function with a user-defined function of the same name.

The following code example demonstrates using the EXTERNAL command to specify a user-defined function in a FORTRAN application.

Sample Code

C Compile options needed: None

      FUNCTION FN (X)
        REAL FN, X
        FN = X
      END

      SUBROUTINE S2 (F, X, Y)
        REAL F, X, Y
        X = F(Y)
      END

      REAL Y, Z, FN
      EXTERNAL FN
      Z = 10.0
      CALL S2(FN, Y, Z)
      WRITE (*, *) Y
      END
                

Additional query words: kbinf 1.00 4.00 4.01 4.10 5.00 5.10

Keywords: kblangfortran KB50401

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