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GDB

gdb
make sure debug flag is enabled when compiling the program. 
e.g., gcc -g 
e.g., set(CMAKE_BUILD_TYPE RelWithDebInfo) or cmake -DCMAKE_BUILD_TYPE=Debug 
gdb <program_name>
gdb --args <program_name> arg1 arg2 arg3
(gdb) break main add a breakpoint at main function
(gdb) r run the program
(gdb) list list current function (in its original programming language)
(gdb) tbreak 48 add a temporary breakpoint at line 48 of current function
(gdb) c continue running the program
(gdb) bt print backtrace (of current stack)
(gdb) print <var> print a variable
(gdb) info locals print all local variables (of current stack)
(gdb) x /x 0x7fffffffd9b0 exam the memory at this address using hex format
(gdb) q quit
More useful commands
(gdb) s step into next function
(gdb) n go to next instruction
(gdb) bt full print full stack info including variables
(gdb) info args print local argc and argv information 
(gdb) whatis v check variable type
(gdb) disas disassemble current function into assembly language
(gdb) list <filename:function_name> list a function
(gdb) list <filename:line_number> list a file around this line number
(gdb) tbreak 0x000055555576bf00 add a temporary breakpoint at the address (of an instruction)
(gdb) x /2xw 0xffff print two-word length of the memory at this address using hex format
b byte, h half-word (2 bytes), w word (4 bytes), g giant word (8 bytes)
x hex, a pointer, c char, d integer, u uint, s string, t binary, f float, o octal
Fancy usage of extended gdb commands
need to download and source stl-views-1.0.3.gdb ; can be added to ~/.gdbinit 
(gdb) pvector <name> print information about the STL vector class std::vector<T> 
(gdb) pmap <name> print information about the STL map class std::map<T,T> 
references: gdb cheatsheet; gdb commands; gdb STL support; download stl-views-1.0.3.gdb; 
Shell
Git
Last modified 2yr ago