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

FILEHDR (4) (not. on PDP-11) FILEHDR ( 4)
NAME
filehdr - file header for common object files
SYNOPSIS
#include
DESCRIPTION
Every common object file begins with a 20-byte header. The following
C struct declaration is used:
struct filehdr
{
} ;
unsigned short
unsigned short
long
long
long
unsigned short
unsigned short
f_magic ;
f_nscns ;
f_timdat ;
f_symptr ;
f_nsyms ;
f_opthdr ;
Ulags ;
I* magic number *I
I* number of sections *I
I* time & date stamp *I
I* file ptr to symtab *I
I* # symtab entries *I
I* sizeof(opt hdr) *I
I* flags *I
F _symptr is the byte offset into the file at which the symbol table
can be found. Its value can be used as the offset in fa eek(3S) to
position an IIO stream to the symbol table. The UNIX optional
header is always 36 bytes. The valid magic numbers are given
below:
#define N3BMAGIC
#define NTVMAGIC
#define V AXWRMAGIC 0570
#define V AXROMAGIC 0575
0550 I* 3B20S *I
0551 I* 3B20S *I
I* VAX writable text segments *I
I* VAX readonly sharab I e text *I
/* segments *I
The value in f_timdat is obtained from the time(2) system call.
Flag bits currently defined are:
#define F _RELFLG 00001 I* relocation entries stripped *I
#define F _EXEC 00002 I* file is executable *I
#define F _LNNO 00004 I* line numbers stripped *I
#define F_LSYMS 00010 I* local symbols stripped *I
#define F_MINMAL 00020 I* minimal object file *I
#define F _UPDATE 00040 I* update file, ogen produced *I
#define F _SWABD 00100 I* file is "pre-swabbed" *I
#define F_AR16WR 00200 I* 16 bit DEC host *I
#define F_AR32WR 00400 I* 32 bit DEC host *I
#define F_AR32W 01000 I* non-DEC host *I
#define F_PATCH 02000 I* "patch" list in opt hdr *I
SEE ALSO
time(2), fseek(3S), a. out( 4).
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