Debugging - GDB tricks
- Some pascal specific patches were excepted; so if possible set language to pascal "set language pascal"
- To get help, use "help <command>" or "help" to see a category list.
- To view datastructures raw, use the "x" command (see "help x")
Examining Type Info
- Q: What function should I use for dumping the type info?
- A: Run x/100c in gdb until it frames. then use 'frame <framenr>' to jump to the correct frame
Inspecting an ansistring
- Q: How do I examine an ansistring?
- A: "x/s <stringname>"
Stop debugger on exception
- Q: How to stop gdb on exception
- A: b fpc_raiseexception
- Q: How to show call stack
- A: bt
Work with breakpoints
- Add: b TObject__Method or b filename.pas:123
- Show: inf b
- Disable: dis 1
- Enble: en 1
- Delete: d 1
- Delete all: d b
when you print the value of a pointer gdb will say something like:
$0 = (MYPTR) 0x0202
If MYPTR is the correct type, you can just use
if it's not the correct type, you can typecast it:
If you do not have a separate type for the actual pointer type, but only a type for what it points to, then the syntax is somewhat awkward because the gdb parser is still showing it's C-heritage in that case: