The ffx debug connect command starts the Fuchsia debugger
(which is called zxdb) for debugging Fuchsia components
on a device.
Concepts
zxdb is Fuchsia’s own debugger that allows you to attach a Fuchsia component
running on a device. Once a component is attached to zxdb, you can perform
interactive debugging operations, such as adding breakpoints, stepping through
code, and inspecting stack traces and variables of the component.
For zxdb to understand and unpack the code of a Fuchsia component,
the component's debug symbols must be available in your development
environment. (For more information on debug symbols, see
Register debug symbols.)
When you run the ffx debug connect command, it establishes a connection to
the Fuchsia device and starts the zxdb terminal on the host machine.
In this terminal, you can use the zxdb commands to
interactively debug Fuchsia components running on the device.
Run the Fuchsia debugger
To start the Fuchsia debugger, run the following command:
ffx debug connect
Once successfully connected to a Fuchsia device, this command starts the
zxdb terminal, for example:
$ ffx debug connect
Connecting (use "disconnect" to cancel)...
Connected successfully.
👉 To get started, try "status" or "help".
[zxdb]
In the zxdb terminal, you can start performing interactive debugging
operations. The example below shows that zxdb is attached to the
memory_monitor component and a breakpoint is created at the
component's main function:
[zxdb] attach memory_monitor.cm
Waiting for process matching "memory_monitor.cm".
Type "filter" to see the current filters.
Attached Process 1 state=Running koid=47467 name=memory_monitor.cm
[zxdb] process
# State Koid Name
▶ 1 Running 47467 memory_monitor.cm
[zxdb] break $main
Created Breakpoint 1 @ $main
48
◉ 49 int main(int argc, const char** argv) {
50 auto command_line = fxl::CommandLineFromArgcArgv(argc, argv);
[zxdb]
To exit the zxdb terminal, type exit or press Ctrl-D.
For more information on usages and best practices on zxdb,
see the zxdb user guide.