Debugger for linux x86_64

Usage

consider the following code:

#include <stdio.h>

int foo(int x)
{
    return x * 2;
}

int main()
{
    int y = foo(5);
    printf("%d\n", y);
    return 0;
}

compiled with

# program must be compiled with debugging info (`-g` flag for gcc for example)
gcc -g -O0 -Wall hello.c -o hello

then debugger could be invoked like this

dbg hello

Commands

breakpoint | break | b

set a breakpoint. Argument is file:line, line or function name, for example

> b hello.c:10 // sets breakpoint on line 10 of file hello.c
> b 10 // sets breakpoint on line 10 of current file
> b foo // sets breakpoint on function's foo start

remove | rm

remove a breakpoint. file:line must be speicified as argument

> rm hello.c:10

list | l

list breakpoints

> l
hello.c:5
hello.c:10

disable

disable breakpoint so execution won't stop on the location

disable hello.c:5

enable

enable breakpoint so execution will stop on the location

enable hello.c:5

clear

remove all breakpoints

clear

run | r

run the program

stop

stop the execution

continue | cont | c

continue execution of the program

step

run the program until next line, for example if we stoped on hello.c:10

> step

now we are on line 11

step-in

run into function call, for example if we stopped on hello.c:10

> step-in

now we are on hello.c:5

step-out

run out of current function, for example if we stopped on hello.c:5

> step-out

now we are on hello.c:11

print | p

print variable

> p s // print variable
const char* s = "hello world"

> p &x // print address of x
int* &x = 0x7ffd8a95df50

> p *y // print value behind pointer
int *y = 10

> p *&x // multiple operators
int *&x = 10

> p foo.x // print field x of struct foo
int x = 15

> p a[0] // print static array element
int a[1] = 10

> p // prints all variables
const char* s = "hello world"
int x = 10
...

set

modify variable

> set *y = 20 // set value behind pointer

> set s = "somebody once told me the world is gonna roll me" // set string

> set foo.x = 30 // set struct field

> set a[1] = 20 // set static array element

> set color = BLUE // set enum variant

> set data.i = 20 // set union field

> set op = mul // set function pointer

location | loc

print current location

> loc
hello.c:5

quit | q

quit the program