a.out.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH a.out 5 RISC
.SH Name
a.out \- assembler and link editor output
.SH Syntax
.B #include <a.out.h>
.SH Description
The 
.PN a.out
.NXR "assembler and link editor"
.NXR "assembler"
.NXR "link editor"
file contains the output from the assembler,
.PN as ,
and the link editor,
.PN ld .
If errors and unresolved references do not exist, both programs make
.PN a.out
executable.  When submitted to the debugger, the
.PN a.out
file provides symbolic information.
.PP
The RISC compilers and ULTRIX compilers
use a file format that is similar to
standard AT&T System V COFF (common object file format).  
.PP
The RISC File Header definition is based on the AT&T System V header file
.I filehdr.h
with the following changes (also see
.MS filehdr 5 ):
.IP \(bu 5
The symbol table file pointer,
.I f_symptr,
and the number of symbol table entries,
.I f_nsyms,
specify the file pointer and the size of the
Symbolic Header, respectively.
.IP \(bu 5
All tables that specify symbolic information have their file
pointers and number of entries in the Symbolic Header.  
.PP
The Optional Header definition uses the same format 
as the System V header file,
.I aouthdr.h,
(the standard (pre-COFF) UNIX system a.out header) except
the following fields have been added:
.I  "bss_start, gprmask, cprmask,"
and
.I gp_value.
.PP
The Section Header definition has the same format as the System V header
file,
.I scnhdr.h,
except the line number fields
.RI ( s_lnnoptr
and
.IR s_nlnno )
are used for gp tables (see
.MS scnhdr 5 ).
.PP
The RISC relocation information definition is similar to that in
Berkeley 4.3 UNIX, which has local relocation types (see
.MS reloc 5 ).
.PP
The RISC file format is as follows:
.IP \(bu 5
File Header
.IP \(bu 5
Optional Header
.IP \(bu 5
Section Headers
.IP \(bu 5
Section Data \(em Includes text, read-only data, large data, 8- and 4-byte
literal pools, small data, small bss (0 size), and large bss (0 size).
.IP \(bu 5
Section Relocation Information \(em Includes information for text, 
read-only data, large data, 8- and 4-byte literal pools, and small data.
.IP \(bu 5
Gp Tables \(em Missing if relocation information is not saved.
.IP \(bu 5
Symbolic Header \(em Missing if fully stripped.
.IP \(bu 5
Line Numbers \(em Created only if debugging is on and missing if stripped of
nonglobals or fully stripped.
.IP \(bu 5
Procedure Descriptor Table \(em Missing if fully stripped.
.IP \(bu 5
Local Symbols \(em Missing if stripped of nonglobals or if fully stripped.
.IP \(bu 5
Optimization Symbols \(em Created only if debugging is on and missing if
stripped of nonglobals or fully stripped.
.IP \(bu 5
Auxiliary Symbols \(em Created only if debugging is on and missing if
stripped of nonglobals or fully stripped.
.IP \(bu 5
Local Strings \(em Missing if stripped of nonglobals or if fully stripped.
.IP \(bu 5
External Strings \(em Missing if fully stripped.
.IP \(bu 5
Relative File Descriptors \(em Missing if stripped of nonglobals or if fully stripped.
.IP \(bu 5
File Descriptors \(em Missing if stripped of nonglobals or if fully stripped.
.IP \(bu 5
External Symbols \(em Missing if fully stripped.
.SH See Also
as(1), ld(1), nm(1), dbx(1), strip(1), filehdr(5), scnhdr(5), reloc(5), 
syms(5), linenum(5).