F2C structure and record

Question

I am using F2C (FORTRAN 77 TO C) to convert a huge FORTRAN code to C. One of my source FORTRAN files has an include file that F2C does not like for some reasons. Here is the include file (TAGLINE.INS) with the extension .INS (I doubt if the extension matters) :

C
C
C***  SCRATCH INPUT DATA FROM FILE FNAM  (.RTV = RAW INPUT TAG VALUE)
C
          STRUCTURE     /STAGRICL/

            CHARACTER*76     UFN     !! U72 FILENAME.UP.CASE     INIT BLANK
            CHARACTER*76     RFN      ! R72 FILENAME.RAWCASE     INIT BLANK
            INTEGER*4        LFN      ! I4  FILENAME.LENGTH      INIT 0    

            CHARACTER*32     USN     !! U32 SECTION-NAME-UP.CASE INIT BLANK
            CHARACTER*32     RSN      ! R32 SECTION-NAME RAWCASE INIT BLANK
            INTEGER*4        LSN      ! I4  SECTION-NAME-LENGTH  INIT 0    

            CHARACTER*32     UTN     !! U32 TAG-NAME-UP.CASE     INIT BLANK
            CHARACTER*32     RTN      ! R32 TAG-NAME-RAWCASE     INIT BLANK
            INTEGER*4        LTN      ! I4  TAG-NAME-LENGTH      INIT 0    

            CHARACTER*80     UTV      ! U80 TAG-VALUE.UP.CASE.IN INIT BLANK
            CHARACTER*80     RTV     !! R80 TAG-VALUE.RAWCASE.IN INIT BLANK
            INTEGER*4        LTV      ! I4  TAG-VALUE-LENGTH     INIT 0    

            CHARACTER*80     RWL      ! R80 TAG-RAW.WHOLE.LINE   INIT BLANK
            INTEGER*4        LWL      ! I4  TAG-RAW.WHOLE.LENGTH INIT 0    
            INTEGER*4        NWL      ! I4  LIN.#.IN.ORIG.FILE   INIT 0    

            LOGICAL*4        SET      ! L4  TAGRICL   SET YET ?  INIT FALSE
            LOGICAL*4        USE      ! L4  TAGRICL  USED YET ?  INIT FALSE

      END STRUCTURE
C
C
      PARAMETER                   (N1000=200)
      RECORD /STAGRICL/   TAGRICL(N1000)  ! 1000.MAX TAG.NAMES.PER.FILE
      COMMON /CTAGRICL/   TAGRICL          ! RETURNED TAG.NAMES+TAG.VALUES

When trying to convert the source code to C using F2C, I get the following errors :

Error on line 5 of TAGLINE.INS: unclassifiable statement (starts "structure/")
Error on line 34 of TAGLINE.INS: unclassifiable statement (starts "record/sta")

Obviously, F2C complains about the structure inside include file (STRUCTURE /STAGRICL/). Fortran 77 comment lines start with character c at the beginning.

My source code is including the .INS file as following :

SUBROUTINE FINDSEC (SECTION,    ISEC1,ISEC2)
C
c------no.mo.$debug.no.no.no
C
      INCLUDE 'TAGLINE.INS'
C
C
      CHARACTER*(*)       SECTION
......rest of the subroutine

Thank you for your help

Use the [tag:fortran] tag for all Fortran questions. Not many people follow just the specific [tag:fortran77] version. And, your code is not even Fortran 77. It is not any standard Fortran. — Vladimir F Героям слава, Apr 30 '20 at 11:43

Vladimir F Героям слава · Accepted Answer · 2020-04-30T11:48:38.877

6

RECORD and STRUCTURE are not standard Fortran and not even a widely supported extension (at least in the days when f2c was really relevant). It is a peculiar extension developed by DEC and hence kept in the later development of the DEC compiler (Compaq and Intel).

These extension have been ported to Gfortran a few years ago but are not supported in the very old compilers like g77 or f2c or even in some current compilers. When compiling using gfortran, these extensions must by allowed by a special flag.

Your options are to rewrite the Fortran code to something that that f2c understands or to translate the code yourself. Or, as people often do in this century, keep your Fortran (+DEC extensions) code, compile it using a current Fortran (+extensions) compiler and call the binary from C.

edited Apr 30 '20 at 11:48

answered Apr 30 '20 at 11:41

Vladimir F Героям слава

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Thanks for your input, Vladimir. Is this a standard FORTRAN syntax ? REAL*4 ZZ [ALLOCATABLE ] (:) what would you recommend as the equivalent type in C/C++ ? – Saeed Apr 30 '20 at 21:01
Also do you have any suggestion how to rewrite STRUCTURE / RECORD block in C? – Saeed Apr 30 '20 at 21:44
@Saeed REAL*4 is not standard Fortran but is widely supported. Allocatable with (:) is Fortran 90. Square brackets in this context are not standard Fortran and I do not know what they mean. – Vladimir F Героям слава Apr 30 '20 at 22:52
DEC Structures will be structs in C, this extension is quite inspired by C. – Vladimir F Героям слава Apr 30 '20 at 22:54

F2C structure and record

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