LINENUM(4)                                             LINENUM(4)



     NAME
          linenum - line number entries in a common object file

     SYNOPSIS
          #include  <linenum.h>

     DESCRIPTION
          The cc command generates an entry in the object file for
          each C source line on which a breakpoint is possible [when
          invoked with the -g option; see cc(1)].  Users can then
          reference line numbers when using the appropriate software
          test system [see sdb(1)].  The structure of these line
          number entries appears below.

          struct  lineno
          {
                  union
                  {
                         long     l_symndx ;
                         long     l_paddr ;
                  }               l_addr ;
                  unsigned short  l_lnno ;
          } ;

          Numbering starts with one for each function.  The initial
          line number entry for a function has l_lnno equal to zero,
          and the symbol table index of the function's entry is in
          l_symndx.  Otherwise, l_lnno is non-zero, and l_paddr is the
          physical address of the code for the referenced line.  Thus
          the overall structure is the following:

                    l_addr                   l_lnno

                    function symtab index    0
                    physical address         line
                    physical address         line
                    ...

                    function symtab index    0
                    physical address         line
                    physical address         line
                    ...


     SEE ALSO
          cc(1), sdb(1), a.out(4).

     ORIGIN
          AT&T V.3






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