linenum(4) DG/UX 5.4R3.00 linenum(4)
NAME
linenum - line number entries in a common object file
SYNOPSIS
#include <linenum.h>
DESCRIPTION
When invoked with the -g option, the cc command generates an entry in
the object file for each C source line on which a breakpoint is
possible. debuggers such as sdb(1) and dbx(1) can then reference
line numbers in the source. The structure of the line number entries
appears below.
struct lineno
{
union
{
long l_symndx ;
long l_paddr ;
} l_addr ;
union
{
struct
{
unsigned short _l_lnno;
unsigned short _l_pad;
} _l_l;
long _l_lnno;
} _l;
} ;
Numbering starts with 1 for each function. The initial line number
entry for a function has llnno equal to zero, and the symbol table
index of the function's entry is in lsymndx. Otherwise, llnno is
non-zero, and lpaddr is the physical address of the code for the
referenced line. Thus the overall structure is the following:
laddr llnno
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), dbx(1), a.out(4).
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