gdb.texinfo

gdb-6.0 linux 下的调试工具

\input texinfo      @c -*-texinfo-*-
@c Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998,
@c 1999, 2000, 2001, 2002, 2003
@c Free Software Foundation, Inc.
@c
@c %**start of header
@c makeinfo ignores cmds prev to setfilename, so its arg cannot make use
@c of @set vars.  However, you can override filename with makeinfo -o.
@setfilename gdb.info
@c
@include gdb-cfg.texi
@c
@settitle Debugging with @value{GDBN}
@setchapternewpage odd
@c %**end of header

@iftex
@c @smallbook
@c @cropmarks
@end iftex

@finalout
@syncodeindex ky cp

@c readline appendices use @vindex, @findex and @ftable,
@c annotate.texi and gdbmi use @findex.
@syncodeindex vr cp
@syncodeindex fn cp

@c !!set GDB manual's edition---not the same as GDB version!
@c This is updated by GNU Press.
@set EDITION Ninth

@c !!set GDB edit command default editor
@set EDITOR /bin/ex

@c THIS MANUAL REQUIRES TEXINFO 4.0 OR LATER.

@c This is a dir.info fragment to support semi-automated addition of
@c manuals to an info tree.
@dircategory Programming & development tools.
@direntry
* Gdb: (gdb).                     The @sc{gnu} debugger.
@end direntry

@ifinfo
This file documents the @sc{gnu} debugger @value{GDBN}.


This is the @value{EDITION} Edition, of @cite{Debugging with
@value{GDBN}: the @sc{gnu} Source-Level Debugger} for @value{GDBN}
Version @value{GDBVN}.

Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998,@*
              1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software'' and ``Free Software Needs
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
and with the Back-Cover Texts as in (a) below.

(a) The Free Software Foundation's Back-Cover Text is: ``You have
freedom to copy and modify this GNU Manual, like GNU software.  Copies
published by the Free Software Foundation raise funds for GNU
development.''
@end ifinfo

@titlepage
@title Debugging with @value{GDBN}
@subtitle The @sc{gnu} Source-Level Debugger
@sp 1
@subtitle @value{EDITION} Edition, for @value{GDBN} version @value{GDBVN}
@author Richard Stallman, Roland Pesch, Stan Shebs, et al.
@page
@tex
{\parskip=0pt
\hfill (Send bugs and comments on @value{GDBN} to bug-gdb\@gnu.org.)\par
\hfill {\it Debugging with @value{GDBN}}\par
\hfill \TeX{}info \texinfoversion\par
}
@end tex

@vskip 0pt plus 1filll
Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
1996, 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
@sp 2
Published by the Free Software Foundation @*
59 Temple Place - Suite 330, @*
Boston, MA 02111-1307 USA @*
ISBN 1-882114-77-9 @*

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software'' and ``Free Software Needs
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
and with the Back-Cover Texts as in (a) below.

(a) The Free Software Foundation's Back-Cover Text is: ``You have
freedom to copy and modify this GNU Manual, like GNU software.  Copies
published by the Free Software Foundation raise funds for GNU
development.''
@end titlepage
@page

@ifnottex
@node Top, Summary, (dir), (dir)

@top Debugging with @value{GDBN}

This file describes @value{GDBN}, the @sc{gnu} symbolic debugger.

This is the @value{EDITION} Edition, for @value{GDBN} Version
@value{GDBVN}.

Copyright (C) 1988-2003 Free Software Foundation, Inc.

@menu
* Summary::                     Summary of @value{GDBN}
* Sample Session::              A sample @value{GDBN} session

* Invocation::                  Getting in and out of @value{GDBN}
* Commands::                    @value{GDBN} commands
* Running::                     Running programs under @value{GDBN}
* Stopping::                    Stopping and continuing
* Stack::                       Examining the stack
* Source::                      Examining source files
* Data::                        Examining data
* Macros::                      Preprocessor Macros
* Tracepoints::                 Debugging remote targets non-intrusively
* Overlays::                    Debugging programs that use overlays

* Languages::                   Using @value{GDBN} with different languages

* Symbols::                     Examining the symbol table
* Altering::                    Altering execution
* GDB Files::                   @value{GDBN} files
* Targets::                     Specifying a debugging target
* Remote Debugging::            Debugging remote programs
* Configurations::              Configuration-specific information
* Controlling GDB::             Controlling @value{GDBN}
* Sequences::                   Canned sequences of commands
* TUI::                         @value{GDBN} Text User Interface
* Interpreters::		Command Interpreters
* Emacs::                       Using @value{GDBN} under @sc{gnu} Emacs
* Annotations::                 @value{GDBN}'s annotation interface.
* GDB/MI::                      @value{GDBN}'s Machine Interface.

* GDB Bugs::                    Reporting bugs in @value{GDBN}
* Formatting Documentation::    How to format and print @value{GDBN} documentation

* Command Line Editing::        Command Line Editing
* Using History Interactively:: Using History Interactively
* Installing GDB::              Installing GDB
* Maintenance Commands::        Maintenance Commands
* Remote Protocol::             GDB Remote Serial Protocol
* Agent Expressions::           The GDB Agent Expression Mechanism
* Copying::			GNU General Public License says
                                how you can copy and share GDB
* GNU Free Documentation License::  The license for this documentation
* Index::                       Index
@end menu

@end ifnottex

@contents

@node Summary
@unnumbered Summary of @value{GDBN}

The purpose of a debugger such as @value{GDBN} is to allow you to see what is
going on ``inside'' another program while it executes---or what another
program was doing at the moment it crashed.

@value{GDBN} can do four main kinds of things (plus other things in support of
these) to help you catch bugs in the act:

@itemize @bullet
@item
Start your program, specifying anything that might affect its behavior.

@item
Make your program stop on specified conditions.

@item
Examine what has happened, when your program has stopped.

@item
Change things in your program, so you can experiment with correcting the
effects of one bug and go on to learn about another.
@end itemize

You can use @value{GDBN} to debug programs written in C and C++.
For more information, see @ref{Support,,Supported languages}.
For more information, see @ref{C,,C and C++}.

@cindex Modula-2
Support for Modula-2 is partial.  For information on Modula-2, see
@ref{Modula-2,,Modula-2}.

@cindex Pascal
Debugging Pascal programs which use sets, subranges, file variables, or
nested functions does not currently work.  @value{GDBN} does not support
entering expressions, printing values, or similar features using Pascal
syntax.

@cindex Fortran
@value{GDBN} can be used to debug programs written in Fortran, although
it may be necessary to refer to some variables with a trailing
underscore.

@value{GDBN} can be used to debug programs written in Objective-C,
using either the Apple/NeXT or the GNU Objective-C runtime.

@menu
* Free Software::               Freely redistributable software
* Contributors::                Contributors to GDB
@end menu

@node Free Software
@unnumberedsec Free software

@value{GDBN} is @dfn{free software}, protected by the @sc{gnu}
General Public License
(GPL).  The GPL gives you the freedom to copy or adapt a licensed
program---but every person getting a copy also gets with it the
freedom to modify that copy (which means that they must get access to
the source code), and the freedom to distribute further copies.
Typical software companies use copyrights to limit your freedoms; the
Free Software Foundation uses the GPL to preserve these freedoms.

Fundamentally, the General Public License is a license which says that
you have these freedoms and that you cannot take these freedoms away
from anyone else.

@unnumberedsec Free Software Needs Free Documentation

The biggest deficiency in the free software community today is not in
the software---it is the lack of good free documentation that we can
include with the free software.  Many of our most important
programs do not come with free reference manuals and free introductory
texts.  Documentation is an essential part of any software package;
when an important free software package does not come with a free
manual and a free tutorial, that is a major gap.  We have many such
gaps today.

Consider Perl, for instance.  The tutorial manuals that people
normally use are non-free.  How did this come about?  Because the
authors of those manuals published them with restrictive terms---no
copying, no modification, source files not available---which exclude
them from the free software world.

That wasn't the first time this sort of thing happened, and it was far
from the last.  Many times we have heard a GNU user eagerly describe a
manual that he is writing, his intended contribution to the community,
only to learn that he had ruined everything by signing a publication
contract to make it non-free.

Free documentation, like free software, is a matter of freedom, not
price.  The problem with the non-free manual is not that publishers
charge a price for printed copies---that in itself is fine.  (The Free
Software Foundation sells printed copies of manuals, too.)  The
problem is the restrictions on the use of the manual.  Free manuals
are available in source code form, and give you permission to copy and
modify.  Non-free manuals do not allow this.

The criteria of freedom for a free manual are roughly the same as for
free software.  Redistribution (including the normal kinds of
commercial redistribution) must be permitted, so that the manual can
accompany every copy of the program, both on-line and on paper.

Permission for modification of the technical content is crucial too.
When people modify the software, adding or changing features, if they
are conscientious they will change the manual too---so they can
provide accurate and clear documentation for the modified program.  A
manual that leaves you no choice but to write a new manual to document
a changed version of the program is not really available to our
community.

Some kinds of limits on the way modification is handled are
acceptable.  For example, requirements to preserve the original
author's copyright notice, the distribution terms, or the list of
authors, are ok.  It is also no problem to require modified versions
to include notice that they were modified.  Even entire sections that
may not be deleted or changed are acceptable, as long as they deal
with nontechnical topics (like this one).  These kinds of restrictions
are acceptable because they don't obstruct the community's normal use
of the manual.

However, it must be possible to modify all the @emph{technical}
content of the manual, and then distribute the result in all the usual
media, through all the usual channels.  Otherwise, the restrictions
obstruct the use of the manual, it is not free, and we need another
manual to replace it.

Please spread the word about this issue.  Our community continues to
lose manuals to proprietary publishing.  If we spread the word that
free software needs free reference manuals and free tutorials, perhaps
the next person who wants to contribute by writing documentation will
realize, before it is too late, that only free manuals contribute to
the free software community.

If you are writing documentation, please insist on publishing it under
the GNU Free Documentation License or another free documentation
license.  Remember that this decision requires your approval---you
don't have to let the publisher decide.  Some commercial publishers
will use a free license if you insist, but they will not propose the
option; it is up to you to raise the issue and say firmly that this is
what you want.  If the publisher you are dealing with refuses, please
try other publishers.  If you're not sure whether a proposed license
is free, write to @email{licensing@@gnu.org}.

You can encourage commercial publishers to sell more free, copylefted
manuals and tutorials by buying them, and particularly by buying
copies from the publishers that paid for their writing or for major
improvements.  Meanwhile, try to avoid buying non-free documentation
at all.  Check the distribution terms of a manual before you buy it,
and insist that whoever seeks your business must respect your freedom.
Check the history of the book, and try to reward the publishers that
have paid or pay the authors to work on it.

The Free Software Foundation maintains a list of free documentation
published by other publishers, at
@url{http://www.fsf.org/doc/other-free-books.html}.

@node Contributors
@unnumberedsec Contributors to @value{GDBN}

Richard Stallman was the original author of @value{GDBN}, and of many
other @sc{gnu} programs.  Many others have contributed to its
development.  This section attempts to credit major contributors.  One
of the virtues of free software is that everyone is free to contribute
to it; with regret, we cannot actually acknowledge everyone here.  The
file @file{ChangeLog} in the @value{GDBN} distribution approximates a
blow-by-blow account.

Changes much prior to version 2.0 are lost in the mists of time.

@quotation
@emph{Plea:} Additions to this section are particularly welcome.  If you
or your friends (or enemies, to be evenhanded) have been unfairly
omitted from this list, we would like to add your names!
@end quotation

So that they may not regard their many labors as thankless, we
particularly thank those who shepherded @value{GDBN} through major
releases:
Andrew Cagney (releases 6.0, 5.3, 5.2, 5.1 and 5.0);