Debugging a GWA application

Different solutions are available to debug a GWA application.

gwadb is the tool provided for debugging GWA applications. For example, to start a debug session in a directory where you have a program called main.4gl, you must first compile your program and then run the debug command:

$ gwadb main

Internally, this command will call gwabuildtool to build the application package in the gwa_dist directory and gwasrv will be called to serve your application in the browser.

Your application opens in the default browser with an address like this:

(Line breaks have been added to improve readability.)

http://localhost:9101/d/r/index.html
             ?fglapp=main&uuid=gwarun2025_01_31_10_18_58_835
             &debug=1&debugSSE=1
             &viaMiniWS=1&t=2025_01_31_10_19_00_309&update=1

A loading page is displayed while waiting for you to start debugging.

Screenshot of loading page when starting to debug a GWA application — Figure: GWA loading

In the terminal, the fgldb debugging tool is running in attached mode to your program, ready to run fgldb commands like run, break, step, continue, quit, and so on.

gwadb main
gwadb:Wait for debuggee.....running fgldb on port:9400
(fgldb) run

For more details about using fgldb tool commands and debugging, go to Starting fglrun in debug mode or type help at the prompt.

Note: Genero Studio graphical debugger

If using Genero Studio, the graphical debugger may be used. For more details, refer to the Packaging for GWA and Graphical Debugger topics in the Genero Studio User Guide.

After quitting the debugger, the browser window should be marked as closed like this:

Screenshot of GWA application page after closing the debugger — Figure: GWA page closing debugger

Example: debug demo

The GWA installation includes a debug demo. To run the demo:

Locate the debug demo. If GWA was installed in FGLDIR, you will find the demo in $FGLDIR/demo/gwa/debug or if installed in a separate directory, you will find it in gwa-install-dir/demo/gwa/debug
If you have make installed, you can run the Makefile included with the demo, which internally compiles the source files and builds the application package in the gwa_dist directory before running the gwadb command:
```
make gwa.debug
```
Or if you also want to build the distribution files, run this target in the makefile:
```
make gwa.debug_build
```
Both commands, start the application in the browser and open fgldb in the terminal.
If not using make, you must compile the demo program first and then run the debug command. For example, If you run the gwadb command with the module to debug, it builds the gwa_dist directory internally:
```
gwadb main 
```
Or you can run the gwadb command with the home page of the application after calling gwabuildtool to build the application package in the default gwa_dist directory:
```
gwabuildtool -p .
gwadb gwa_dist/index.html 
```
Both commands, start the application in the browser and open fgldb in the terminal for debugging.