Basics
When an app was created with debug mode and is running in on a device, it is possible to
switch the runtime system in debug mode, by using the
fgldb
command tool with the
-m option.
Important: The app
must have be created in debug mode. Apps created in release mode cannot be debugged
with the
fgldb tool. For more details, check how to build mobile
apps with debug mode in the
Deploying mobile apps section.
Important: On iOS devices, after installing the app, you need to enable the
debug port in the app settings, otherwise the app will not listen to the debug
port.
The
fgldb command line tool takes two arguments: The host (or IP
address) of the mobile device, and an optional TCP port number to connect to. For
mobile devices, the debug TCP port is
6400. Note that this is the
same port the mobile front-end is listening to for GUI connection, when working in
GUI client/server mode.
Debugging an app running on a physical device
Considering the mobile device IP address is "
192.168.1.23", and the
application is running locally on a physical mobile device, you can open a debug
session from the development machine as
follows:
$ fgldb -m 192.168.1.23:6400
108 DISPLAY ARRAY contlist TO sr.*
(fgldb)
The
(fgldb) prompt indicates that you are now connected to the fglrun
process on mobile device, and the program flow is suspended. To continue with the
program flow, enter the "
continue" debugger
command:
(fgldb) continue
Continuing.
The application will then resume on the mobile device. To suspend the program again and
enter debugger commands, press CTRL-C in the debug console:
fgldb
will show the interrupt message and give you the control
back:
...
Continuing.
^CINTERRUPT
108 DISPLAY ARRAY contlist TO sr.*
(fgldb)
At this point, you can for example set a break point and continue until the break point
is
reached:
(fgldb) b 427
Breakpoint 2 at 0x00000000: file contacts.4gl, line 427.
(fgldb) continue
Continuing.
Breakpoint 2, edit_contact() at contacts.4gl:427
427 IF new THEN
(fgldb)
To finish the debug session, close the connection with the "
detach"
debugger
command:
(fgldb) detach
Connection closed by foreign host.
Debugging an app running on an Android device emulator
When the mobile application is executing on an Android device emulator in the same machine as the
development environment, you must first redirect the 6400 TCP port.
First you must connect to the emulator terminal, using the telnet TCP port 5554:
$ telnet localhost 5554
When connected on the device emulator, redirect the port 6400 as
follows:
$ redir add tcp:6400:6400
$ quit
You may also want to redirect the port 6480, to be able to show GMA service debug
information from a browser with the
http://localhost:6480
URL:
$ redir add tcp:6480:6480
Finally, quit the device emulator telnet session
with:
$ quit