NAME

scnhdr − section header for a common object file

SYNOPSIS

#include  <scnhdr.h>

DESCRIPTION

Every common object file has a table of section headers to specify the layout of the data within the file.  Each section within an object file has its own header.  The C structure appears below. 

struct scnhdr
{
     char            s_name[SYMNMLEN]; /∗ section name ∗/
     long            s_paddr;/∗ physical address ∗/
     long            s_vaddr;/∗ virtual address ∗/
     long            s_size;/∗ section size ∗/
     long            s_scnptr;/∗ file ptr to raw data ∗/
     long            s_relptr;/∗ file ptr to relocation ∗/
     long            s_lnnoptr;/∗ file ptr to line numbers ∗/
     unsigned long   s_nreloc;/∗ # reloc entries ∗/
     unsigned long   s_nlnno;/∗ # line number entries ∗/
     long            s_flags;/∗ flags ∗/
} ;

File pointers are byte offsets into the file; they can be used as the offset in a call to fseek(3S).  If a section is initialized, the file contains the actual bytes.  An uninitialized section is somewhat different.  It has a size, symbols defined in it, and symbols that refer to it.  But it can have no relocation entries, line numbers, or data.  Consequently, an uninitialized section has no raw data in the object file, and the values for s_scnptr, s_relptr, s_lnnoptr, s_nreloc, and s_nlnno are zero. 

SEE ALSO

fseek(3S), a.out(4). 
pld(1) in the CX/UX User’s Reference Manual. 

CX/UX Programmer’s Reference Manual