reloc(4)                                                 reloc(4)



NAME
     reloc - relocation information for a common object file

SYNOPSIS
     #include <reloc.h>

DESCRIPTION
     Object files have one relocation entry for each relocatable
     reference in the text or data.  If relocation information is
     present, it will be in the following format.

        struct     reloc
        {
          long     r_vaddr ;   /* (virtual) address of
                                   reference */
          long     r_symndx ;  /* index into symbol table */
          short    r_type ;    /* relocation type */
        } ;


        /*
         * All generics
         * reloc already performed to symbol in the
         * same section
         */
        #define  R_ABS      0

        /*
         * DEC Processors  VAX 11/780 and VAX 11/750
         *
         */
        #define R_RELBYTE   017
        #define R_RELWORD   020
        #define R_RELLONG   021
        #define R_PCRBYTE   022
        #define R_PCRWORD   023
        #define R_PCRLONG   024

        /*
         * Motorola 68000 uses R_RELBYTE, R_RELWORD, R_RELLONG,
         * R_PCRBYTE, and R_PCRWORD as for DEC machines above.
         */


     As the link editor reads each input section and performs
     relocation, the relocation entries are read.  They direct
     how references found within the input section are treated.

     R_ABS
          The reference is absolute, and no relocation is
          necessary.  The entry will be ignored.




January 1992                                                    1

reloc(4)                                                 reloc(4)



     R_RELBYTE
          A direct 8-bit reference to a symbol's virtual address.

     R_RELWORD
          A direct 16-bit reference to a symbol's virtual
          address.

     R_RELLONG
          A direct 32-bit reference to a symbol's virtual
          address.

     R_PCRBYTE
          A ``PC-relative'' 8-bit reference to a symbol's virtual
          address.

     R_PCRWORD
          A ``PC-relative'' 16-bit reference to a symbol's
          virtual address.

     R_PCRLONG
          A ``PC-relative'' 32-bit reference to a symbol's
          virtual address.

     On the VAX processors, relocation of a symbol index of -1
     indicates that the relative difference between the current
     segment's start address and the program's load address is
     added to the relocatable address.

     Other relocation types will be defined as they are needed.

     Relocation entries are generated automatically by the
     assembler and automatically utilized by the link editor.  A
     link editor option exists for removing the relocation
     entries from an object file.

SEE ALSO
     a.out(4), syms(4)

     ld(1), strip(1) in A/UX Command Reference
















2                                                    January 1992