Depurar el código es como cazar. Caza de insectos.
- Amit Kalantri
¿Qué es GDB?
GNU Debugger es un depurador portátil para el proyecto GNU que se ejecuta en muchos sistemas similares a UNIX y puede depurar muchos lenguajes de programación, incluidos C, C ++, Free Pascal, FreeBASIC, Ada, Fortran y Rust. GDB es un software gratuito publicado bajo la licencia GPL.
Fuente: GNU Debugger - Wikipedia
GDB — , .
, , , GDB.
, — , . , , :
| Caesar::shift | Caesar |
| Caesar::ChangeShift | Caesar |
| Caesar::Crypt | Caesar |
(TUI)
TUI, GDB, , , . TUI GDB tui enable
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breakpoint
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b Method if variable == value
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:
(gdb) b Crypt if Caesar::shift == 1 Note: breakpoint 2 also set at pc 0x4026e3. Breakpoint 4 at 0x4026e3: file Caesar.h, line 55.
Crypt()
, Caesar
shift
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(gdb) display Caesar::shift 1: Caesar::shift = <error: Cannot reference non-static field "shift"> (gdb) n Breakpoint 2, Caesar::Crypt (this=0x7fffffffdc30, text="Crypt this text! Btw, xyz") at Caesar.h:55 1: Caesar::shift = 1 (gdb) n 1: Caesar::shift = 1 (gdb)
:
(gdb) display *stringArrayForOutput@lengthOfArray 1: *stringArrayForOutput@lengthOfArray = {"Etarv vjku vgzv! Dvy, zab", "Fubsw wklv whaw! Ewz, abc", "Gvctx xlmw xibx! Fxa, bcd"} (gdb)
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(gdb) explore Caesar::shift 'Caesar::shift' is a scalar value of type 'int'. Caesar::shift = 6 (gdb) explore Caesar 'Caesar' is a struct/class with the following fields: letters = <Enter 0 to explore this field of type 'std::string'> shift = <Enter 1 to explore this field of type 'int'>
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(gdb) target record-full (gdb) p Caesar::shift $1 = 6 (gdb) n (gdb) p Caesar::shift $2 = 7 (gdb) reverse-next No more reverse-execution history. (gdb) p Caesar::shift $3 = 6
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info local
:
(gdb) info local mainObj = {letters = "abcdefghijklmnopqrstuvwxyz", shift = 1} textForC = "Crypt this text! Btw, xyz" cryptedText = "Dszqu uijt ufyu! Cux, yza" outputVariants = 0x402280 <_start>
, info variables
:
(gdb) info variables All defined variables: File /usr/include/c++/10/bits/basic_string.h: 101: const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::size_type std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::npos; File /usr/include/c++/10/bits/stl_pair.h: 83: static const std::piecewise_construct_t std::piecewise_construct; File /usr/include/c++/10/iostream: 74: static std::ios_base::Init std::__ioinit; Non-debugging symbols: 0x00000000004002e8 __abi_tag 0x0000000000403000 _IO_stdin_used 0x00000000004031b8 typeinfo for std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > 0x00000000004031e0 typeinfo name for std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > --Type <RET> for more, q to quit, c to continue without paging--
info b
:
(gdb) info b Num Type Disp Enb Address What 1 breakpoint keep y 0x0000000000402633 in Caesar::ChangeShift() at Caesar.h:31 breakpoint already hit 1 time 2 breakpoint keep y 0x00000000004026e3 in Caesar::Crypt(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) at Caesar.h:55 breakpoint already hit 1 time
whatis
:
(gdb) whatis Caesar::shift type = int (gdb) whatis Caesar type = Caesar
, info address
:
(gdb) info address Caesar::Crypt Symbol "Caesar::Crypt(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)" is a function at address 0x4026be.
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Este artículo no incluye algunos comandos que son fáciles de entender , por ejemplo: ejecutar, detener, salir, etc. No los especifiqué a propósito, ya que el artículo intenta transmitir información que los usuarios de GDB podrían no conocer. Si tiene alguna sugerencia sobre cómo complementar el artículo, con mucho gusto leeré los comentarios.