05-led-roulette GDB problem.

[houshilifeng]

When I am debugging as the book said and entered "target remote :1337" in the gdb mode, here is the outcome:
Remote debugging using :1337
warning: No executable has been specified and target does not support
determining executable automatically. Try using the "file" command.
0x00000100 in ?? ()
Have I done something wrong?
Waiting for answers.
Thanks.

[Jzow]

My judgment is that your console gdb is not loaded into the device target.

As stated in the book, you should select different devices according to the micro:bit version. In addition, the GDB command of cargo-embed is not very stable, and may not recognize all the commands sent to it by GDB

Is it convenient for you to send the shell command you entered?

[AlexanderRitter02]

Hope I'm not assuming too much, but I may be able to help.

Since I likely came across the same issue using the gdb command from the book, getting exactly the same output.
This happens if GDB doesn't find the executable.

Note that the section in the book is a bit unclear on which directory to switch to in the new shell:

Since cargo-embed is blocking our current shell we can simply open a new one and cd back into our project directory.

I initially assumed the "project directory" would be the same directory I ran cargo-embed in, e.g. microbit/src/05-led-roulette.
However for me, the program was compiled into microbit/target/thumbv7em-none-eabihf/debug/led-roulette.

Fixing this is very simple:

1. In your debugging shell, go to the directory: discovery-master/microbit.
2. Run the gdb command, e.g. gdb-multiarch target/thumbv7em-none-eabihf/debug/led-roulette
3. Make sure GDB says something like:
   Reading symbols from target/thumbv7em-none-eabihf/debug/led-roulette..., otherwise it doesn't make sense running the next commands.

If you still have issues, you can always just use the absolute path. Cargo embed will tell you where it places the file in the output with "Target: <path>".

[dilnozacs]

thanks @AlexanderRitter02 it worked!!

[eldruin]

Fixed in #520