$DEBUG is precompiler Metacommand, which enables debugging features, allowing you to step through your code running line by line and to inspect variables and change their values in real time.
- $DEBUG injects extra code in the resulting binary, allowing the IDE to control the execution flow of your program.
- When $DEBUG is used, the IDE will connect to your running program using a local TCP/IP connection.
- You may get a prompt from your Operating System regarding this, so it may be necessary to allow the IDE to receive connections.
- No external connections are created, and your running program will only attempt to connect locally to the IDE.
- The default TCP/IP port starts at 9001. Multiple running instances of the IDE will attempt to open ports 9002 and up.
- You can change the base port in the Debug menu.
- The metacommand is supposed to be removed once your program is ready for release, although leaving it in won’t have any effect if your program isn’t run from the IDE.
- The only drawback of leaving the metacommand in is that your binary will end up being larger than required.
$DEBUG Mode Operation
- To start execution in pause mode, you can use F7 or F8.
- There will be an arrow next to the line number where execution is paused, indicating the next line that will be run.
- When you enable $DEBUG mode, you can set breakpoints by clicking the line number at which you wish to stop execution. This can also be achieved by using the F9 key.
- Breakpoints are indicated by a red dot next to the line number.
- To clear all breakpoints, hit F10.
- To skip a line during execution, shift-click a line number
- Lines marked for skipping are indicated by an exclamation mark next to the line number.
- F4 opens the Variable List dialog, which allows you to add variables to the Watch List.
- During execution, the Variable List dialog also allows you to set the values of variables and also to create Watchpoints.
- Watchpoints halt execution, similarly to breakpoints, but do so when a variable matches the condition you specify.
- You can use relational operators (=, <>, >=, <=, >, <) to create watchpoint conditions.
- After a breakpoint or a watchpoint is reached, F5 can be used to continue execution.
- F6 can be used when the execution pointer is inside a sub/function. When used, execution will proceed until the procedure is ended.
- F7 can be used to run line by line, and can be used to debug code inside subs/functions (Step Into).
- F8 can be used to run line by line without entering sub/function calls (Step Over).
- F12 can be used to show the current call stack (which procedure calls led to the current line).