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  • 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>
Last modified 2yr ago