CNDBA社区
1 GDB 概述
gdb是GNU开源组织发布的一个强大的Linux下的程序调试工具。
一般来说，GDB主要帮助你完成下面四个方面的功能：
1、启动你的程序，可以按照你的自定义的要求随心所欲的运行程序。
2、可让被调试的程序在你所指定的调置的断点处停住。（断点可以是条件表达式）
3、当程序被停住时，可以检查此时你的程序中所发生的事。
4、你可以改变你的程序，将一个BUG产生的影响修正从而测试其他BUG。
GDB主要来调试C/C++语言写的程序，当然也就可以调试其他语言程序。
gdb使用shell命令gdb来调用，一旦开始，就从终端读取命令直到gdb退出。可以不带任何参数或选项执行gdb命令，但是最常用的启动gdb的方式是带一个或者两个参数，指定一个可执行文件来作为参数:
gdb program (gdb+可执行文件名称)
也可以在gdb文件后面指定可执行文件 和 core文件的名称:
gdb program core（gdb + 可执行文件 +core文件）
也可以指定一个进程id作为第二个参数，如果你想调试一个正在运行的程序：
gdb program 1234（gdb进程名+进程id）
会附件gdb到进程1234上(除非有一个文件名“1234”；GDB首先检查core文件)
相关参数列表
| 命令 | 命令缩写 | 命令说明 |
|---|---|---|
| list | l | 显示多行源代码 |
| break | b | 设置断点,程序运行到断点的位置会停下来 |
| info | i | 描述程序的状态 |
| run | r | 开始运行程序 |
| display | disp | 跟踪查看某个变量,每次停下来都显示它的值 |
| step | s | 执行下一条语句,如果该语句为函数调用,则进入函数执行其中的第一条语句 |
| next | n | 执行下一条语句,如果该语句为函数调用,不会进入函数内部执行(即不会一步步地调试函数内部语句) |
| p | 打印内部变量值 | |
| continue | c | 继续程序的运行,直到遇到下一个断点 |
| set var name=v | 设置变量的值 | |
| start | st | 开始执行程序,在main函数的第一条语句前面停下来 |
| file | 装入需要调试的程序 | |
| kill | k | 终止正在调试的程序 |
| watch | 监视变量值的变化 | |
| backtrace | bt | 产看函数调用信息(堆栈) |
| frame | f | 查看栈帧 |
| quit | q | 退出GDB环境 |
2 GDB 命令帮助
直接在操作系统层面执行help 查看：
[dave@www.cndba.cn bin]$ gdb -help
This is the GNU debugger. Usage:
gdb [options] [executable-file [core-file or process-id]]
gdb [options] --args executable-file [inferior-arguments ...]
gdb [options] [--python|-P] script-file [script-arguments ...]
Options:
--args Arguments after executable-file are passed to inferior
-b BAUDRATE Set serial port baud rate used for remote debugging.
--batch Exit after processing options.
--batch-silent As for --batch, but suppress all gdb stdout output.
--return-child-result
GDB exit code will be the child's exit code.
--cd=DIR Change current directory to DIR.
--command=FILE, -x Execute GDB commands from FILE.
--eval-command=COMMAND, -ex
Execute a single GDB command.
May be used multiple times and in conjunction
with --command.
--core=COREFILE Analyze the core dump COREFILE.
--pid=PID Attach to running process PID.
--dbx DBX compatibility mode.
--directory=DIR Search for source files in DIR.
--epoch Output information used by epoch emacs-GDB interface.
--exec=EXECFILE Use EXECFILE as the executable.
--fullname Output information used by emacs-GDB interface.
--help Print this message.
--interpreter=INTERP
Select a specific interpreter / user interface
-l TIMEOUT Set timeout in seconds for remote debugging.
--nw Do not use a window interface.
--nx Do not read .gdbinit file.
--python, -P Following argument is Python script file; remaining
arguments are passed to script.
--quiet Do not print version number on startup.
--readnow Fully read symbol files on first access.
--readnever Do not read symbol files.
--se=FILE Use FILE as symbol file and executable file.
--symbols=SYMFILE Read symbols from SYMFILE.
--tty=TTY Use TTY for input/output by the program being debugged.
--tui Use a terminal user interface.
--version Print version information and then exit.
-w Use a window interface.
--write Set writing into executable and core files.
--xdb XDB compatibility mode.
At startup, GDB reads the following init files and executes their commands:
For more information, type "help" from within GDB, or consult the
GDB manual (available as on-line info or a printed manual).
Report bugs to "<http://www.gnu.org/software/gdb/bugs/>".
[dave@www.cndba.cn bin]$
(gdb) help
List of classes of commands:
aliases -- Aliases of other commands
breakpoints -- Making program stop at certain points
data -- Examining data
files -- Specifying and examining files
internals -- Maintenance commands
obscure -- Obscure features
running -- Running the program
stack -- Examining the stack
status -- Status inquiries
support -- Support facilities
tracepoints -- Tracing of program execution without stopping the program
user-defined -- User-defined commands
Type "help" followed by a class name for a list of commands in that class.
Type "help all" for the list of all commands.
Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.
(gdb) help all
Command class: aliases
ni -- Step one instruction
rc -- Continue program being debugged but run it in reverse
rni -- Step backward one instruction
rsi -- Step backward exactly one instruction
si -- Step one instruction exactly
stepping -- Specify single-stepping behavior at a tracepoint
tp -- Set a tracepoint at specified line or function
tty -- Set terminal for future runs of program being debugged
where -- Print backtrace of all stack frames
ws -- Specify single-stepping behavior at a tracepoint
Command class: breakpoints
awatch -- Set a watchpoint for an expression
break -- Set breakpoint at specified line or function
catch -- Set catchpoints to catch events
catch assert -- Catch failed Ada assertions
catch catch -- Catch an exception
catch exception -- Catch Ada exceptions
catch exec -- Catch calls to exec
catch fork -- Catch calls to fork
catch syscall -- Catch system calls by their names and/or numbers
catch throw -- Catch an exception
catch vfork -- Catch calls to vfork
clear -- Clear breakpoint at specified line or function
commands -- Set commands to be executed when a breakpoint is hit
condition -- Specify breakpoint number N to break only if COND is true
delete -- Delete some breakpoints or auto-display expressions
delete bookmark -- Delete a bookmark from the bookmark list
delete breakpoints -- Delete some breakpoints or auto-display expressions
delete checkpoint -- Delete a checkpoint (experimental)
delete display -- Cancel some expressions to be displayed when program stops
delete mem -- Delete memory region
---Type <return> to continue, or q <return> to quit---
delete tracepoints -- Delete specified tracepoints
delete tvariable -- Delete one or more trace state variables
disable -- Disable some breakpoints
disable breakpoints -- Disable some breakpoints
disable display -- Disable some expressions to be displayed when program stops
disable mem -- Disable memory region
disable tracepoints -- Disable specified tracepoints
enable -- Enable some breakpoints
enable breakpoints -- Enable some breakpoints
enable breakpoints delete -- Enable breakpoints and delete when hit
enable breakpoints once -- Enable breakpoints for one hit
enable delete -- Enable breakpoints and delete when hit
enable display -- Enable some expressions to be displayed when program stops
enable mem -- Enable memory region
enable once -- Enable breakpoints for one hit
enable tracepoints -- Enable specified tracepoints
ftrace -- Set a fast tracepoint at specified line or function
hbreak -- Set a hardware assisted breakpoint
ignore -- Set ignore-count of breakpoint number N to COUNT
rbreak -- Set a breakpoint for all functions matching REGEXP
rwatch -- Set a read watchpoint for an expression
save -- Save breakpoint definitions as a script
save breakpoints -- Save current breakpoint definitions as a script
save gdb-index -- Save a
save tracepoints -- Save current tracepoint definitions as a script
strace -- Set a static tracepoint at specified line
tbreak -- Set a temporary breakpoint
tcatch -- Set temporary catchpoints to catch events
tcatch assert -- Catch failed Ada assertions
tcatch catch -- Catch an exception
tcatch exception -- Catch Ada exceptions
tcatch exec -- Catch calls to exec
tcatch fork -- Catch calls to fork
tcatch syscall -- Catch system calls by their names and/or numbers
tcatch throw -- Catch an exception
tcatch vfork -- Catch calls to vfork
---Type <return> to continue, or q <return> to quit---
thbreak -- Set a temporary hardware assisted breakpoint
trace -- Set a tracepoint at specified line or function
watch -- Set a watchpoint for an expression
……
(gdb)
