Cannot bind breakpoint with MDbg (always unbound and ineffective)

Question

I cannot set any working (not unbound) breakpoints with command line MDbg (.Net Managed Code Debugger) with C# modules compiled with csc on command line as well under Windows 10. I spent an entire day trying to figure out how to fix this to absolutely no avail. Here are detailed steps I took to show this strange trouble.

Details

Installed MDbg with NuGet 4.4.1.4656:

nuget install MDbg -Version 0.1.0

And set path to xxx/NuGet/MDbg.0.1.0/tools Then compiled a simple test C# source (tried with .Net frameworks 3.5 and 4.7 with same issue):

csc /debug+ /optimize- test0.cs

Contents of test0.cs:

using System;
using System.Collections.Generic;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
           int max;
           try   {max=int.Parse(args[0]);}
           catch {max=222;}
           List<int> primes = CollectPrimesUpTo(max);
           Console.WriteLine(String.Join(", ", primes.ConvertAll(i => i.ToString()).ToArray()));
        }
        static List<int> CollectPrimesUpTo(int max)
        {
            List<int> result = new List<int>();
            for(int i=1; i<=max; i++) {
             int j, sq = (int)Math.Sqrt((double)i);
             for(j=2; j<=sq; j++) {
              if(i % j == 0)
               break;
             }
             if(j>sq)
              result.Add(i);
            }  
           return result;
        }
    }
}

Below is an debug session, started under the same folder where test0.cs|.exe|.pdb are located, with different attempts to set breakpoints (many more tried anyway): all unbound and not working because the go command runs programs to its end. [Something strange also is setting path is needed for show command to work. Otherwise you get this ridiculous message: "Error: Source file 'b:_limbo\GUIonCSharpMono-master\test0.cs' not available."]

D:\_limbo\GUIonCSharpMono-master>Mdbg test0 23
MDbg (Managed debugger) v0.0.0.0 started.
Copyright (C) Microsoft Corporation. All rights reserved.
For information about commands type "help";
to exit program type "quit".
run test0 23
STOP: Breakpoint Hit
located at line 9 in test0.cs
[p#:0, t#:0] mdbg> path D:\_limbo\GUIonCSharpMono-master
Path set to: D:\_limbo\GUIonCSharpMono-master
6      class Program
7      {
8          static void Main(string[] args)
9:*        {
10             int max;
11             try   {max=int.Parse(args[0]);}
[p#:0, t#:0] mdbg> x test0
~0. ConsoleApplication1.Program.Main(args)
~1. ConsoleApplication1.Program.CollectPrimesUpTo(max)
~2. ConsoleApplication1.Program..ctor()
~3. ConsoleApplication1.Program.<Main>b__0(i)
[p#:0, t#:0] mdbg> break ~1
Breakpoint #1 unbound (:1!ConsoleApplication1.Program::CollectPrimesUpTo(+0))
[p#:0, t#:0] mdbg> break CollectPrimesUpTo
Breakpoint #2 unbound (::CollectPrimesUpTo(+0))
[p#:0, t#:0] mdbg> break ConsoleApplication1.Program.CollectPrimesUpTo
Breakpoint #3 unbound (ConsoleApplication1.Program::CollectPrimesUpTo(+0))
[p#:0, t#:0] mdbg> break test0.cs:25
Breakpoint #4 unbound (line 25 in test0.cs)
[p#:0, t#:0] mdbg> break
Current breakpoints:
Breakpoint #1 unbound (:1!ConsoleApplication1.Program::CollectPrimesUpTo(+0))
Breakpoint #2 unbound (::CollectPrimesUpTo(+0))
Breakpoint #3 unbound (ConsoleApplication1.Program::CollectPrimesUpTo(+0))
Breakpoint #4 unbound (line 25 in test0.cs)
[p#:0, t#:0] mdbg> go
1, 2, 3, 5, 7, 11, 13, 17, 19, 23
STOP: Process Exited
mdbg> exit
D:\_limbo\GUIonCSharpMono-master>

Any help, solution, suggestion, idea, highly appreciated. Thank you.

Users creating nuget packages like this is not exactly a great idea. Keep in mind that mdbg is a *sample*, it was meant to show programmers how to create their own debugger. Not meant for production use, the user interface is pretty minimal and don't expect to get good error messages. And "mono" is notable, not so sure that Mono follows the .NET debugger interface closely enough to allow mdbg to work. A similar tool made for Mono [is here](https://github.com/mono/sdb). — Hans Passant, Dec 08 '17 at 09:53
I agree and thank you for your reply. The idea is to port some code on Mono (and thank you for the pointer to its debugger), but presently I don't use Mono! I use .Net framework with csc! You're also right to say MDbg is just a toy and an example. But some people succeeded to at least set a valid breakpoint. Still, as I now target Native Windows with csc on command line, I would like to have some basic debug utility. And I far as I know the only candidate in this framework is MDbg. Any other would be also welcome but I don't think any exists. — Djee, Dec 08 '17 at 10:11

score 1 · Answer 1 · answered May 10 '20 at 10:33

By me the issue was that the PDB file was in the new "Portable" PDB file format that was introduced with .Net Core, however MDbg only understand the legacy "Windows" or "Full" PDB format that was used originally with .Net Framework, so in order for it to work use the option when compiling to create full instead of portable.

Cannot bind breakpoint with MDbg (always unbound and ineffective)

1 Answers1