Use gdb to debug the program

background

First of all, we need to understand the following:
1. There are two ways to release the program, debug mode and release mode
2. The binary program out of Linux gcc/g++, the default is release mode
3. To use gdb to debug, it must be in the source code Add the -g option when generating the binary program

What is gdb

gdb is a command line-based, powerful program debugging tool released by the gnu open source organization under the UNIX/LINUX operating system.

manual

1. Enter gdb binFile to enter debugging
2. Debug command explanation

list 行号：显示binFile源代码，接着上次的位置往下列，每次列10行
list 函数名：列出某个函数的源代码
r或run：运行程序
n或next：单条执行
s或step：进入函数调用
break（b）行号：在某一行开头设置断点
info break：查看断断点信息
finsh：执行到当前函数返回，然后停下来等待命令
print(p)：打印表达式的值，通过表达式可以修改变量的值或者调用函数
p 变量：打印变量的值
set var：修改变量的值
continue(c)：从当前位置开始连续而非单步执行程序
run(r)：从开始连续而非单步执行程序
delete breakpoints：删除所有断点
delete breakpoints n：删除序号为n的断点
disable breakpoints：禁用断点
info(或i) breakopints：参看当前设置了那些断点
display 变量名：跟踪查看一个变量，每次停下来都显示它的值
undisplay：取消对先前设置的那些变量的跟踪
until X行号：跳至X行
breaktrace(bt)：查看各级函数调用及参数
info(i) local：查看当前栈局部变量的值
quit：退出gdb
CTRL + d:退出gdb

Note: You must use -g when compiling a program debugged with gdb, otherwise the problem of No symbol table is loaded. Use the "file" command. will appear.