# GDB Call Stack

**The call stack** is the chain of function calls that led to the current execution point. Navigating it helps you understand how you reached an error and inspect variables in each caller.

```bash
(gdb) backtrace                 # show all stack frames
(gdb) backtrace 10              # show last 10 frames
(gdb) frame 0                   # select innermost frame (current function)
(gdb) frame 3                   # select frame 3 (third caller up)
(gdb) up                        # move to caller
(gdb) down                      # move to callee
(gdb) info frame                # details of current frame
(gdb) info locals               # locals in current frame
(gdb) info args                 # arguments to current frame
```

Backtrace prints the entire stack: frame 0 (current), frame 1 (its caller), frame 2 (caller's caller), etc. Each line shows the function name, source file, and line number.

Frame numbering: frame 0 is innermost (where execution paused); higher numbers are older calls. `frame N` jumps directly to frame N. `up` and `down` navigate one step at a time—faster when you need to glance at one or two nearby frames.

Once you select a frame with `frame N`, all commands operate in that frame's scope. `print x` shows `x` as it exists in that frame. `info locals` and `info args` show that frame's variables and arguments.

`info frame` shows the current frame's details: memory addresses, return address, saved registers, etc.—useful for understanding the calling convention or debugging stack corruption.

To debug a crash, run `backtrace` immediately—it shows the call chain that led to the crash. Select each frame to inspect its arguments and locals and understand what went wrong.