AT&T UNIX™PC Unix System V Users Manual - tenox

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SCNHDR ( 4) SCNHDR ( 4)
NAME
scnhdr - section header for a common object file
SYNOPSIS
#include
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
long
long
long
long
long
long
unsigned short
unsigned short
long
s_name[SYMNMLEN]; I* section name *I
s_paddr; I* physical address *I
s_vaddr; I* virtual address *I
s_size; I* section size *I
s_scnptr; I* file ptr to raw data *I
s_relptr; I* file ptr to relocation *I
s_lnnoptr; I* file ptr to line numbers *I
s_nreloc; I* # reloc entries *I
s_nlnno; I* # line number entries *I
s_flags; I* flags *I
File pointers are byte offsets into the file; they can be used as the
offset in a call to fs eek(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
ld( l ), fseek(3S), a. out( 4).
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