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[Solved] C::B Watches window acting weird

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BlueHazzard:
Hi, i can reproduce your bug, but i am afraid we can not do anything about this easily (more at the end)....

I have modified your example like this:

--- Code: ---#define strLength 60

/* function prototypes */
void sort(char [][strLength], int);
/* void swap(char [], char []);  */

int main(void)
{
   char names[4][strLength] = {"Florida000000000000000000000xxxxxxxxxxxxxxxxxxxxxx",
                               "Oregon",
                               "California",
                               "Georgia"};

--- End code ---

now if we look at the output of the gdb log we get this:

--- Code: ---> output names
->{"Florida", '0' <repeats 21 times>, 'x' <repeats 22 times>, "\000\000\000\000\000\000\000\000\000", "Oregon", '\000' <repeats 53 times>, "California", '\000' <repeats 49 times>, "Georgia", '\000' <repeats 52 times>}

--- End code ---
as here is visible gdb does not give us any hints where the nested array is ending (the names) and where the next is starting. As you would expect because internally a multi dimensional array in c is a continuous memory block.
The only way to distinguishe this would be to count the actual elements. So first look at the output of the what is call

--- Code: ---> whatis names
->type = char [4][60]

--- End code ---
and then parse the output of "names" accordingly by counting all characters and <repeats x times> occurrences.
This will probably not happen....
 
AndrewCot is currently working on a new type of gdb plugin, that makes output parsing a lot better (see https://forums.codeblocks.org/index.php/topic,25058.0.html ) I will look into this the next week and i think we will probably introduce this plugin in codeblocks in the future for a better debugging experience.
I have not tested it until now, so i do not know exactly if this "quirk" you have reported is different in the new plugin...

AndrewCot:
I have not seen a GDB client for DAP. If anyone knows of one or finds one please let me know as I would like to test it.

I will put this on my list, but due to the slow progress I am making with getting the ProjectExport Cmake output files working with the C::B project files I think BlueHazzard will get to check it out before me. I will check the GDB/MI plugin to see if it works or not, but this plugin is only available as source and as such is not available for non C::B devs to try.

BlueHazzard:

--- Quote ---I have not seen a GDB client for DAP. If anyone knows of one or finds one please let me know as I would like to test it.
--- End quote ---
Oh... i was thinking visual studio has a DAP for GDB? Is this only for llvm? Anyway, will check it out, with time comes for sure a DAP plugin for gdb, so i think investing in this plugin is a good idea.

In the mean time i have found a fix for this. You can enter the following command in the debugger command field (in the debugger log is a field where you can enter commands at the bottom):

--- Code: ---set print array on
--- End code ---
And re add the variables to the watches. This should fix the print problem. I am investigating a bit and probably commit an auto call to this in the gdb plugin...

AndrewCot:
Just got back to this one.

You should be able use the GDB debugger initialization commands to send the command automatically to GDB. This is done via the Settings->Debugger... menu and then on the left select the debugger you are using and then enter the command in the 'Debugger initialization commands" text box and press OK. I have used this to load the python pretty printers in the past.

It is my understanding that Visual Studio Code (VSC) GDB interface uses the GDM/MI interface as the DAP interface was only added a few years ago, but GDB has been available for years before that, but I could be wrong. VSC LLDB debugger does use the DAP interface and so do a number of the other debuggers for other languages. DAP is from VSC, but has been added to a number of other IDE's all ready and the list is growing as time progresses. I agree with the DAP GDB & DAP plugin feedback.

stuarte:
Good morning gentlemen,

First, please accept my apologies for the tardiness of this reply.

@AndrewCot: I have followed your advice and entered the "set print array on" into the Debugger initialization commands box in Settings/Debugger.../default. I then single-stepped the program and found that both before and after sorting the Watches window now showed each element of names[] on its own line, that is names[0] on the first line, names[1] on the second line and so on.

@BlueHazzard: Having implemented Mr Cot's advice and found it to work, do I also need to enter the "set print array on" command into the debugger command field (in the debugger log) or are these two different ways to achieve the same result ?

Anyway, I would like to thank you gentlemen for your very responsive help in this particular matter and the whole team for bringing forth C::B in the first place and thereby making debugger access and usage (at least at the basic level) so very easy.

Stuart

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