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                                                               filehdr(4)



        _________________________________________________________________
        filehdr                                               File Format
        file header for executable files in DG/UX
        _________________________________________________________________


        SYNTAX

        #include <filehdr.h>


        DESCRIPTION

        Every executable file begins with a 204-byte header declared in
        filehdr.h.  The following C struct declaration is used:

             struct nsection
              { unsigned int logical_start;
                unsigned int logical_length;
                unsigned int file_start;
                unsigned int file_length;
                unsigned int file_reloc;
                unsigned int file_reloc_length;
                unsigned int attributes;
              };

             struct prformat
              { unsigned short magic_number;       /*  magic                 */
                unsigned short format_rev_number;  /*  format rev. number    */
                unsigned short num_non_exec_sect;  /*  # of non-exec.  sects */
                unsigned short num_exec_sect;      /*  # of executable sects */
                struct nsection syshead;        /*  system header */
                struct nsection symbolt;        /*  symbol table  */
                struct nsection ds;             /*                */
                struct nsection dl;             /*                */
                struct nsection lt;             /*                */
                struct nsection exec[2];        /*  two executable sections */
              };

        The DG/UX system header is 26 bytes.  The valid magic number is
        given below:

             #define DGRTWDMAGIC 0457
                  /* DG MV/Family read-only text, writeable data segments
                  */


        SEE ALSO

        a.out(4).




        DG/UX 4.00                                                 Page 1
               Licensed material--property of copyright holder(s)





                                                               filehdr(4)



        CAVEATS

        The executable file format is used only for executable files
        (load modules), not for object files.


















































        DG/UX 4.00                                                 Page 2
               Licensed material--property of copyright holder(s)



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