# GDB Advanced Features

**GDB supports Python scripting, remote debugging, and signal handling**. These features enable automation, distributed debugging, and fine-grained control over program behavior.

## Python Scripting

GDB allows Python scripts to inspect and control programs. Define custom commands or automate debugging tasks:

```bash
(gdb) python
> import gdb
> frame = gdb.selected_frame()
> print(frame.name())
> end

(gdb) define pprint
  python
    frame = gdb.selected_frame()
    print(f"Function: {frame.name()}")
  end
end
```

Access program state from Python: `gdb.selected_frame()` returns the current frame; `gdb.breakpoints()` lists breakpoints; `gdb.execute(cmd)` runs a GDB command. Combine these to script complex debugging workflows.

## Remote Debugging

Debug a program running on another machine using `gdbserver`. Start the remote server, then connect from your local GDB:

```bash
# On remote machine
gdbserver localhost:1234 ./program

# On local machine
gdb ./program
(gdb) target remote hostname:1234
(gdb) break main
(gdb) continue
```

`gdbserver` is lightweight and does not require GDB on the remote machine—only on your local machine. Useful for embedded systems or production servers.

## Signal Handling

Control how GDB handles signals (SIGTERM, SIGSEGV, etc.):

```bash
(gdb) handle SIGTERM stop       # pause on SIGTERM
(gdb) handle SIGPIPE nostop     # ignore SIGPIPE, don't pause
(gdb) handle SIGUSR1 print      # print message but don't pause
(gdb) catch signal SIGUSR1      # breakpoint on signal (alternative syntax)
(gdb) info signals              # list all signals
```

By default, some signals pause (SIGSEGV) and others don't (SIGPIPE). `handle` lets you change this. Useful for debugging signal handlers or ignoring noisy signals in production code.

## Pretty Printing

Configure how complex types print:

```bash
(gdb) define pp
  set print pretty on
  print $arg0
  set print pretty off
end
```

Write Python pretty-printers to customize output of user-defined types (classes, structs). Saves time inspecting complex data structures.

## Debugging Optimization

Compile with `-O0 -g` for reliable debugging. If you must debug optimized code (`-O2`), GDB loses variable information and instruction order becomes unpredictable. Some variables may be optimized away entirely.

Remote debugging and signal handling are essential for production debugging; Python scripting is useful for automating repetitive debugging patterns.