GDB(1)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GNU Development Tools\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GDB(1)<\/p>\n
NAME<\/p>\n
gdb – The GNU Debugger<\/p>\n
SYNOPSIS<\/p>\n
gdb [-help] [-nh] [-nx] [-q] [-batch] [-cd=dir] [-f] [-b bps]
\n[-tty=dev] [-s symfile] [-e prog] [-se prog] [-c core]
\n[-p procID]
\n[-x cmds] [-d dir] [prog|prog procID|prog core]<\/p>\n
DESCRIPTION<\/p>\n
The purpose of a debugger such as GDB is to allow you to see what is
\ngoing on “inside” another program while it executes — or what
\nanother program was doing at the moment it crashed.<\/p>\n
GDB can do four main kinds of things (plus other things in support of
\nthese) to help you catch bugs in the act:<\/p>\n
\u00b7\u00a0\u00a0 Start your program, specifying anything that might affect its
\nbehavior.<\/p>\n
\u00b7\u00a0\u00a0 Make your program stop on specified conditions.<\/p>\n
\u00b7\u00a0\u00a0 Examine what has happened, when your program has stopped.<\/p>\n
\u00b7\u00a0\u00a0 Change things in your program, so you can experiment with
\ncorrecting the effects of one bug and go on to learn about
\nanother.<\/p>\n
You can use GDB to debug programs written in C,\u00a0C@t{++}, Fortran and
\nModula-2.<\/p>\n
GDB is invoked with the shell command “gdb”.\u00a0 Once started, it reads
\ncommands from the terminal until you tell it to exit with the GDB
\ncommand “quit”.\u00a0 You can get online help from GDB itself by using the
\ncommand “help”.<\/p>\n
You can run “gdb” with no arguments or options; but the most usual
\nway to start GDB is with one argument or two, specifying an
\nexecutable program as the argument:<\/p>\n
gdb program<\/p>\n
You can also start with both an executable program and a core file
\nspecified:<\/p>\n
gdb program core<\/p>\n
You can, instead, specify a process ID as a second argument, if you
\nwant to debug a running process:<\/p>\n
gdb program 1234
\ngdb -p 1234<\/p>\n
would attach GDB to process 1234 (unless you also have a file named
\n1234; GDB does check for a core file first).\u00a0 With option -p you can
\nomit the program filename.<\/p>\n
Here are some of the most frequently needed GDB commands:<\/p>\n
break [file:]functiop
\nSet a breakpoint at function (in file).<\/p>\n
run [arglist]
\nStart your program (with arglist, if specified).<\/p>\n
bt\u00a0 Backtrace: display the program stack.<\/p>\n
print expr
\nDisplay the value of an expression.<\/p>\n
c\u00a0\u00a0 Continue running your program (after stopping, e.g. at a
\nbreakpoint).<\/p>\n
next
\nExecute next program line (after stopping); step over any
\nfunction calls in the line.<\/p>\n
edit [file:]function
\nlook at the program line where it is presently stopped.<\/p>\n
list [file:]function
\ntype the text of the program in the vicinity of where it is
\npresently stopped.<\/p>\n
step
\nExecute next program line (after stopping); step into any
\nfunction calls in the line.<\/p>\n
help [name]
\nShow information about GDB command name, or general information
\nabout using GDB.<\/p>\n
quit
\nExit from GDB.<\/p>\n
For full details on GDB, see Using GDB: A Guide to the GNU Source-
\nLevel Debugger, by Richard M. Stallman and Roland H. Pesch.\u00a0 The same
\ntext is available online as the “gdb” entry in the “info” program.<\/p>\n
OPTIONS<\/p>\n
Any arguments other than options specify an executable file and core
\nfile (or process ID); that is, the first argument encountered with no
\nassociated option flag is equivalent to a -se option, and the second,
\nif any, is equivalent to a -c option if it’s the name of a file.
\nMany options have both long and short forms; both are shown here.
\nThe long forms are also recognized if you truncate them, so long as
\nenough of the option is present to be unambiguous.\u00a0 (If you prefer,
\nyou can flag option arguments with + rather than -, though we
\nillustrate the more usual convention.)<\/p>\n
All the options and command line arguments you give are processed in
\nsequential order.\u00a0 The order makes a difference when the -x option is
\nused.<\/p>\n
-help
\n-h\u00a0 List all options, with brief explanations.<\/p>\n
-symbols=file
\n-s file
\nRead symbol table from file file.<\/p>\n
-write
\nEnable writing into executable and core files.<\/p>\n
-exec=file
\n-e file
\nUse file file as the executable file to execute when appropriate,
\nand for examining pure data in conjunction with a core dump.<\/p>\n
-se=file
\nRead symbol table from file file and use it as the executable
\nfile.<\/p>\n
-core=file
\n-c file
\nUse file file as a core dump to examine.<\/p>\n
-command=file
\n-x file
\nExecute GDB commands from file file.<\/p>\n
-ex command
\nExecute given GDB command.<\/p>\n
-directory=directory
\n-d directory
\nAdd directory to the path to search for source files.<\/p>\n
-nh Do not execute commands from ~\/.gdbinit.<\/p>\n
-nx
\n-n\u00a0 Do not execute commands from any .gdbinit initialization files.<\/p>\n
-quiet
\n-q\u00a0 “Quiet”.\u00a0 Do not print the introductory and copyright messages.
\nThese messages are also suppressed in batch mode.<\/p>\n
-batch
\nRun in batch mode.\u00a0 Exit with status 0 after processing all the
\ncommand files specified with -x (and .gdbinit, if not inhibited).
\nExit with nonzero status if an error occurs in executing the GDB
\ncommands in the command files.<\/p>\n
Batch mode may be useful for running GDB as a filter, for example
\nto download and run a program on another computer; in order to
\nmake this more useful, the message<\/p>\n
Program exited normally.<\/p>\n
(which is ordinarily issued whenever a program running under GDB
\ncontrol terminates) is not issued when running in batch mode.<\/p>\n
-cd=directory
\nRun GDB using directory as its working directory, instead of the
\ncurrent directory.<\/p>\n
-fullname
\n-f\u00a0 Emacs sets this option when it runs GDB as a subprocess.\u00a0 It
\ntells GDB to output the full file name and line number in a
\nstandard, recognizable fashion each time a stack frame is
\ndisplayed (which includes each time the program stops).\u00a0 This
\nrecognizable format looks like two \\032 characters, followed by
\nthe file name, line number and character position separated by
\ncolons, and a newline.\u00a0 The Emacs-to-GDB interface program uses
\nthe two \\032 characters as a signal to display the source code
\nfor the frame.<\/p>\n
-b bps
\nSet the line speed (baud rate or bits per second) of any serial
\ninterface used by GDB for remote debugging.<\/p>\n
-tty=device
\nRun using device for your program’s standard input and output.<\/p>\n
SEE ALSO<\/p>\n
The full documentation for GDB is maintained as a Texinfo manual.\u00a0 If
\nthe “info” and “gdb” programs and GDB’s Texinfo documentation are
\nproperly installed at your site, the command<\/p>\n
info gdb<\/p>\n
should give you access to the complete manual.<\/p>\n
Using GDB: A Guide to the GNU Source-Level Debugger, Richard M.
\nStallman and Roland H. Pesch, July 1991.<\/p>\n
COPYRIGHT<\/p>\n
Copyright (c) 1988-2013 Free Software Foundation, Inc.<\/p>\n
Permission is granted to copy, distribute and\/or modify this document
\nunder the terms of the GNU Free Documentation License, Version 1.3 or
\nany later version published by the Free Software Foundation; with the
\nInvariant Sections being “Free Software” and “Free Software Needs
\nFree Documentation”, with the Front-Cover Texts being “A GNU Manual,”
\nand with the Back-Cover Texts as in (a) below.<\/p>\n
(a) The FSF’s Back-Cover Text is: “You are free to copy and modify
\nthis GNU Manual.\u00a0 Buying copies from GNU Press supports the FSF in
\ndeveloping GNU and promoting software freedom.”<\/p>\n
COLOPHON<\/p>\n
This page is part of the gdb (GNU debugger) project.\u00a0 Information
\nabout the project can be found at \u27e8http:\/\/www.gnu.org\/software\/gdb\/\u27e9.
\nIf you have a bug report for this manual page, see
\n\u27e8http:\/\/www.gnu.org\/software\/gdb\/bugs\/\u27e9.\u00a0 This page was obtained from
\nthe project’s upstream Git read-only mirror of the CVS repository
\n(git:\/\/sourceware.org\/git\/gdb.git) on 2014-12-30.\u00a0 If you discover
\nany rendering problems in this HTML version of the page, or you
\nbelieve there is a better or more up-to-date source for the page, or
\nyou have corrections or improvements to the information in this
\nCOLOPHON (which is not part of the original manual page), send a mail
\nto\u00a0man-pages@man7.org<\/p>\n
gdb-7.6.50.20131021-cvs\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2013-12-12\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GDB(1)<\/p>\n","protected":false},"excerpt":{"rendered":"
GDB(1)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GNU Development Tools\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GDB(1) NAME gdb – The GNU Debugger SYNOPSIS gdb [-help] [-nh] [-nx] [-q] [-batch] [-cd=dir] [-f] [-b bps] [-tty=dev] [-s symfile] [-e prog] [-se prog] [-c core] [-p procID] [-x cmds] [-d dir] [prog|prog procID|prog core] DESCRIPTION The purpose of a debugger such as GDB is to allow you to see […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_sitemap_exclude":false,"_sitemap_priority":"","_sitemap_frequency":"","footnotes":""},"categories":[8],"tags":[],"class_list":["post-322","post","type-post","status-publish","format-standard","hentry","category-shell"],"a3_pvc":{"activated":false,"total_views":0,"today_views":0},"_links":{"self":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts\/322","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=322"}],"version-history":[{"count":0,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts\/322\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=322"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=322"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=322"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}