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INFO-DIR-SECTION Programming & development tools.

START-INFO-DIR-ENTRY

* Gdb: (gdb).                     The GNU debugger.

END-INFO-DIR-ENTRY

   This file documents the GNU debugger GDB.

   This is the Ninth Edition, December 2001, of `Debugging with GDB:

the GNU Source-Level Debugger' for GDB Version 5.3.

   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,

1998,

1999, 2000, 2001, 2002 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."

File: gdb.info,  Node: General Query Packets,  Next: Register Packet Format,  Prev: Stop Reply Packets,  Up: Remote Protocol

General Query Packets

=====================

   The following set and query packets have already been defined.

`q'`C' -- current thread

     Return the current thread id.

     Reply:

    ``QC'PID'

          Where PID is a HEX encoded 16 bit process id.

    `*'

          Any other reply implies the old pid.

`q'`fThreadInfo' - all thread ids

     `q'`sThreadInfo'

     Obtain a list of active thread ids from the target (OS).  Since

     there may be too many active threads to fit into one reply packet,

     this query works iteratively: it may require more than one

     query/reply sequence to obtain the entire list of threads.  The

     first query of the sequence will be the `qf'`ThreadInfo' query;

     subsequent queries in the sequence will be the `qs'`ThreadInfo'

     query.

     NOTE: replaces the `qL' query (see below).

     Reply:

    ``m'ID'

          A single thread id

    ``m'ID,ID...'

          a comma-separated list of thread ids

    ``l''

          (lower case 'el') denotes end of list.

     In response to each query, the target will reply with a list of

     one or more thread ids, in big-endian hex, separated by commas.

     GDB will respond to each reply with a request for more thread ids

     (using the `qs' form of the query), until the target responds with

     `l' (lower-case el, for `'last'').

`q'`ThreadExtraInfo'`,'ID -- extra thread info

     Where ID is a thread-id in big-endian hex.  Obtain a printable

     string description of a thread's attributes from the target OS.

     This string may contain anything that the target OS thinks is

     interesting for GDB to tell the user about the thread.  The string

     is displayed in GDB's `info threads' display.  Some examples of

     possible thread extra info strings are "Runnable", or "Blocked on

     Mutex".

     Reply:

    `XX...'

          Where XX... is a hex encoding of ASCII data, comprising the

          printable string containing the extra information about the

          thread's attributes.

`q'`L'STARTFLAGTHREADCOUNTNEXTTHREAD -- query LIST or THREADLIST *(deprecated)*

     Obtain thread information from RTOS.  Where: STARTFLAG (one hex

     digit) is one to indicate the first query and zero to indicate a

     subsequent query; THREADCOUNT (two hex digits) is the maximum

     number of threads the response packet can contain; and NEXTTHREAD

     (eight hex digits), for subsequent queries (STARTFLAG is zero), is

     returned in the response as ARGTHREAD.

     NOTE: this query is replaced by the `q'`fThreadInfo' query (see

     above).

     Reply:

    ``q'`M'COUNTDONEARGTHREADTHREAD...'

          Where: COUNT (two hex digits) is the number of threads being

          returned; DONE (one hex digit) is zero to indicate more

          threads and one indicates no further threads; ARGTHREADID

          (eight hex digits) is NEXTTHREAD from the request packet;

          THREAD...  is a sequence of thread IDs from the target.

          THREADID (eight hex digits).  See

          `remote.c:parse_threadlist_response()'.

`q'`CRC:'ADDR`,'LENGTH -- compute CRC of memory block

     Reply:

    ``E'NN'

          An error (such as memory fault)

    ``C'CRC32'

          A 32 bit cyclic redundancy check of the specified memory

          region.

`q'`Offsets' -- query sect offs

     Get section offsets that the target used when re-locating the

     downloaded image.  _Note: while a `Bss' offset is included in the

     response, GDB ignores this and instead applies the `Data' offset

     to the `Bss' section._

     Reply:

    ``Text='XXX`;Data='YYY`;Bss='ZZZ'

`q'`P'MODETHREADID -- thread info request

     Returns information on THREADID.  Where: MODE is a hex encoded 32

     bit mode; THREADID is a hex encoded 64 bit thread ID.

     Reply:

    `*'

     See `remote.c:remote_unpack_thread_info_response()'.

`q'`Rcmd,'COMMAND -- remote command

     COMMAND (hex encoded) is passed to the local interpreter for

     execution.  Invalid commands should be reported using the output

     string.  Before the final result packet, the target may also

     respond with a number of intermediate `O'OUTPUT console output

     packets.  _Implementors should note that providing access to a

     stubs's interpreter may have security implications_.

     Reply:

    `OK'

          A command response with no output.

    `OUTPUT'

          A command response with the hex encoded output string OUTPUT.

    ``E'NN'

          Indicate a badly formed request.

    ``''

          When `q'`Rcmd' is not recognized.

`qSymbol::' -- symbol lookup

     Notify the target that GDB is prepared to serve symbol lookup

     requests.  Accept requests from the target for the values of

     symbols.

     Reply:

    ``OK''

          The target does not need to look up any (more) symbols.

    ``qSymbol:'SYM_NAME'

          The target requests the value of symbol SYM_NAME (hex

          encoded).  GDB may provide the value by using the

          `qSymbol:'SYM_VALUE:SYM_NAME message, described below.

`qSymbol:'SYM_VALUE:SYM_NAME -- symbol value

     Set the value of SYM_NAME to SYM_VALUE.

     SYM_NAME (hex encoded) is the name of a symbol whose value the

     target has previously requested.

     SYM_VALUE (hex) is the value for symbol SYM_NAME.  If GDB cannot

     supply a value for SYM_NAME, then this field will be empty.

     Reply:

    ``OK''

          The target does not need to look up any (more) symbols.

    ``qSymbol:'SYM_NAME'

          The target requests the value of a new symbol SYM_NAME (hex

          encoded).  GDB will continue to supply the values of symbols

          (if available), until the target ceases to request them.

File: gdb.info,  Node: Register Packet Format,  Next: Examples,  Prev: General Query Packets,  Up: Remote Protocol

Register Packet Format

======================

   The following `g'/`G' packets have previously been defined.  In the

below, some thirty-two bit registers are transferred as sixty-four

bits.  Those registers should be zero/sign extended (which?)  to fill

the space allocated.  Register bytes are transfered in target byte

order.  The two nibbles within a register byte are transfered

most-significant - least-significant.

MIPS32

     All registers are transfered as thirty-two bit quantities in the

     order: 32 general-purpose; sr; lo; hi; bad; cause; pc; 32

     floating-point registers; fsr; fir; fp.

MIPS64

     All registers are transfered as sixty-four bit quantities

     (including thirty-two bit registers such as `sr').  The ordering

     is the same as `MIPS32'.

File: gdb.info,  Node: Examples,  Prev: Register Packet Format,  Up: Remote Protocol

Examples

========

   Example sequence of a target being re-started.  Notice how the

restart does not get any direct output:

     -> `R00'

     <- `+'

     _target restarts_

     -> `?'

     <- `+'

     <- `T001:1234123412341234'

     -> `+'

   Example sequence of a target being stepped by a single instruction:

     -> `G1445...'

     <- `+'

     -> `s'

     <- `+'

     _time passes_

     <- `T001:1234123412341234'

     -> `+'

     -> `g'

     <- `+'

     <- `1455...'

     -> `+'

File: gdb.info,  Node: Copying,  Next: GNU Free Documentation License,  Prev: Remote Protocol,  Up: Top

GNU GENERAL PUBLIC LICENSE

**************************

                         Version 2, June 1991

     Copyright (C) 1989, 1991 Free Software Foundation, Inc.

     59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

     Everyone is permitted to copy and distribute verbatim copies

     of this license document, but changing it is not allowed.

Preamble

========

   The licenses for most software are designed to take away your

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File: gdb.info,  Node: GNU Free Documentation License,  Next: Index,  Prev: Copying,  Up: Top

GNU Free Documentation License

******************************

                        Version 1.1, March 2000

     Copyright (C) 2000  Free Software Foundation, Inc.

     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

     Everyone is permitted to copy and distribute verbatim copies

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  0. PREAMBLE

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     Page" means the text near the most prominent appearance of the

     work's title, preceding the beginning of the body of the text.

  2. VERBATIM COPYING

     You may copy and distribute the Document in any medium, either

     commercially or noncommercially, provided that this License, the

     copyright notices, and the license notice saying this License

     applies to the Document are reproduced in all copies, and that you

     add no other conditions whatsoever to those of this License.  You

     may not use technical measures to obstruct or control the reading

     or further copying of the copies you make or distribute.  However,

     you may accept compensation in exchange for copies.  If you

     distribute a large enough number of copies you must also follow

     the conditions in section 3.

     You may also lend copies, under the same conditions stated above,

     and you may publicly display copies.

  3. COPYING IN QUANTITY

     If you publish printed copies of the Document numbering more than

     100, and the Document's license notice requires Cover Texts, you

     must enclose the copies in covers that carry, clearly and legibly,

     all these Cover Texts: Front-Cover Texts on the front cover, and

     Back-Cover Texts on the back cover.  Both covers must also clearly

     and legibly identify you as the publisher of these copies.  The

     front cover must present the full title with all words of the

     title equally prominent and visible.  You may add other material

     on the covers in addition.  Copying with changes limited to the

     covers, as long as they preserve the title of the Document and

     satisfy these conditions, can be treated as verbatim copying in

     other respects.

     If the required texts for either cover are too voluminous to fit

     legibly, you should put the first ones listed (as many as fit

     reasonably) on the actual cover, and continue the rest onto

     adjacent pages.

     If you publish or distribute Opaque copies of the Document

     numbering more than 100, you must either include a

     machine-readable Transparent copy along with each Opaque copy, or

     state in or with each Opaque copy a publicly-accessible

     computer-network location containing a complete Transparent copy

     of the Document, free of added material, which the general

     network-using public has access to download anonymously at no

     charge using public-standard network protocols.  If you use the

     latter option, you must take reasonably prudent steps, when you

     begin distribution of Opaque copies in quantity, to ensure that

     this Transparent copy will remain thus accessible at the stated

     location until at least one year after the last time you

     distribute an Opaque copy (directly or through your agents or

     retailers) of that edition to the public.

     It is requested, but not required, that you contact the authors of

     the Document well before redistributing any large number of

     copies, to give them a chance to provide you with an updated

     version of the Document.

  4. MODIFICATIONS

     You may copy and distribute a Modified Version of the Document

     under the conditions of sections 2 and 3 above, provided that you

     release the Modified Version under precisely this License, with

     the Modified Version filling the role of the Document, thus

     licensing distribution and modification of the Modified Version to

     whoever possesses a copy of it.  In addition, you must do these

     things in the Modified Version:

     A. Use in the Title Page (and on the covers, if any) a title

     distinct    from that of the Document, and from those of previous

     versions    (which should, if there were any, be listed in the

     History section    of the Document).  You may use the same title

     as a previous version    if the original publisher of that version

     gives permission.

     B. List on the Title Page, as authors, one or more persons or

     entities    responsible for authorship of the modifications in the

     Modified    Version, together with at least five of the principal

     authors of the    Document (all of its principal authors, if it

     has less than five).

     C. State on the Title page the name of the publisher of the

     Modified Version, as the publisher.

     D. Preserve all the copyright notices of the Document.

     E. Add an appropriate copyright notice for your modifications

     adjacent to the other copyright notices.

     F. Include, immediately after the copyright notices, a license

     notice    giving the public permission to use the Modified Version

     under the    terms of this License, in the form shown in the

     Addendum below.

     G. Preserve in that license notice the full lists of Invariant

     Sections    and required Cover Texts given in the Document's

     license notice.

     H. Include an unaltered copy of this License.

     I. Preserve the section entitled "History", and its title, and add

     to    it an item stating at least the title, year, new authors, and

       publisher of the Modified Version as given on the Title Page.

     If    there is no section entitled "History" in the Document,

     create one    stating the title, year, authors, and publisher of

     the Document as    given on its Title Page, then add an item

     describing the Modified    Version as stated in the previous

     sentence.

     J. Preserve the network location, if any, given in the Document for

       public access to a Transparent copy of the Document, and

     likewise    the network locations given in the Document for

     previous versions    it was based on.  These may be placed in the

     "History" section.     You may omit a network location for a work

     that was published at    least four years before the Document

     itself, or if the original    publisher of the version it refers

     to gives permission.

     K. In any section entitled "Acknowledgements" or "Dedications",

     preserve the section's title, and preserve in the section all the

      substance and tone of each of the contributor acknowledgements

     and/or dedications given therein.

     L. Preserve all the Invariant Sections of the Document,

     unaltered in their text and in their titles.  Section numbers

     or the equivalent are not considered part of the section titles.

     M. Delete any section entitled "Endorsements."  Such a section

     may not be included in the Modified Version.

     N. Do not retitle any existing section as "Endorsements"    or to

     conflict in title with any Invariant Section.

     If the Modified Version includes new front-matter sections or

     appendices that qualify as Secondary Sections and contain no

     material copied from the Document, you may at your option

     designate some or all of these sections as invariant.  To do this,

     add their titles to the list of Invariant Sections in the Modified

     Version's license notice.  These titles must be distinct from any

     other section titles.

     You may add a section entitled "Endorsements", provided it contains

     nothing but endorsements of your Modified Version by various

     parties-for example, statements of peer review or that the text has

     been approved by an organization as the authoritative definition

     of a standard.

     You may add a passage of up to five words as a Front-Cover Text,

     and a passage of up to 25 words as a Back-Cover Text, to the end

     of the list of Cover Texts in the Modified Version.  Only one

     passage of Front-Cover Text and one of Back-Cover Text may be

     added by (or through arrangements made by) any one entity.  If the

     Document already includes a cover text for the same cover,

     previously added by you or by arrangement made by the same entity

     you are acting on behalf of, you may not add another; but you may

     replace the old one, on explicit permission from the previous

     publisher that added the old one.

     The author(s) and publisher(s) of the Document do not by this

     License give permission to use their names for publicity for or to

     assert or imply endorsement of any Modified Version.

  5. COMBINING DOCUMENTS

     You may combine the Document with other documents released under

     this License, under the terms defined in section 4 above for

     modified versions, provided that you include in the combination

     all of the Invariant Sections of all of the original documents,

     unmodified, and list them all as Invariant Sections of your

     combined work in its license notice.

     The combined work need only contain one copy of this License, and

     multiple identical Invariant Sections may be replaced with a single

     copy.  If there are multiple Invariant Sections with the same name

     but different contents, make the title of each such section unique

     by adding at the end of it, in parentheses, the name of the

     original author or publisher of that section if known, or else a

     unique number.  Make the same adjustment to the section titles in

     the list of Invariant Sections in the license notice of the

     combined work.

     In the combination, you must combine any sections entitled

     "History" in the various original documents, forming one section

     entitled "History"; likewise combine any sections entitled

     "Acknowledgements", and any sections entitled "Dedications."  You

     must delete all sections entitled "Endorsements."

  6. COLLECTIONS OF DOCUMENTS

     You may make a collection consisting of the Document and other

     documents released under this License, and replace the individual

     copies of this License in the various documents with a single copy

     that is included in the collection, provided that you follow the

     rules of this License for verbatim copying of each of the

     documents in all other respects.

     You may extract a single document from such a collection, and

     distribute it individually under this License, provided you insert

     a copy of this License into the extracted document, and follow

     this License in all other respects regarding verbatim copying of

     that document.

  7. AGGREGATION WITH INDEPENDENT WORKS

     A compilation of the Document or its derivatives with other

     separate and independent documents or works, in or on a volume of

     a storage or distribution medium, does not as a whole count as a

     Modified Version of the Document, provided no compilation

     copyright is claimed for the compilation.  Such a compilation is

     called an "aggregate", and this License does not apply to the

     other self-contained works thus compiled with the Document, on

     account of their being thus compiled, if they are not themselves

     derivative works of the Document.

     If the Cover Text requirement of section 3 is applicable to these

     copies of the Document, then if the Document is less than one

     quarter of the entire aggregate, the Document's Cover Texts may be

     placed on covers that surround only the Document within the

     aggregate.  Otherwise they must appear on covers around the whole

     aggregate.

  8. TRANSLATION

     Translation is considered a kind of modification, so you may

     distribute translations of the Document under the terms of section

     4.  Replacing Invariant Sections with translations requires special

     permission from their copyright holders, but you may include

     translations of some or all Invariant Sections in addition to the

     original versions of these Invariant Sections.  You may include a

     translation of this License provided that you also include the

     original English version of this License.  In case of a

     disagreement between the translation and the original English

     version of this License, the original English version will prevail.

  9. TERMINATION

     You may not copy, modify, sublicense, or distribute the Document

     except as expressly provided for under this License.  Any other

     attempt to copy, modify, sublicense or distribute the Document is

     void, and will automatically terminate your rights under this