NATVIS errors/warnings are not reported in cppvsdbg debugger output #10343

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1. guusw commented on Jun 20, 2023

   

   Guus Waals (guusw)

   on Jun 20, 2023

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   Is there any way to see the errors somewhere else even if they're not in the debugger output?
2. akkiss commented on Jul 2, 2023

   

   Ákos Kiss (akkiss)

   on Jul 2, 2023

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   I'm struggling with this as well. Trying to use a natvis file but nothing happens, don't know why, it would be nice to see some feedback on loading the natvis file.
3. Nerixyz commented on Jan 31, 2025

   

   Nerixyz (Nerixyz)

   on Jan 31, 2025

   More actions

   Since Microsoft doesn't seem to care about this, we have to resort to binary patching¹. Make sure to create a backup before (or use my script which does that automatically).

   In the extension directory, ($Env:USERPROFILE\extensions\ms-vscode.cpptools-1.23.5-win32-x64), navigate to debugAdapters\vsdbg\bin, open CppDebug.dll, and set the byte at position 0x39FD9 to one of the following values:

   • Off: 5 (default)
   • Error: 3
   • Warning: 2
   • Verbose: 1

   For convenience, I made a PowerShell script that does just that (and verifies the edits). You don't need to restart VS Code.

   Script

   Usage:

   > .\SetNatvisLogLevel.ps1 Warning
   Set level to Warning

   param (
       [Parameter(Position = 0, Mandatory)]
       [ValidateSet('Off', 'Error', 'Warning', 'Verbose')]
       [string] $Level,
   
       [string] $VsCodeDir = "$Env:USERPROFILE\.vscode" 
   )
   
   $ErrorActionPreference = 'Stop';
   
   function FindCppToolsExtension {
       param (
           [string] $ExtensionsDir
       )
       
       $dirs = Get-ChildItem $ExtensionsDir -Filter "ms-vscode.cpptools*" -Directory;
   
       if ($dirs.Length -ne 1) {
           throw "No 'ms-vscode.cpptools*' directory found in '$ExtensionsDir'";
       }
   
       return $dirs[0].FullName;
   }
   
   function BackupOriginalFile {
       param (
           [string] $Path,
           [string] $DesiredHash
       )
       
       $curHash = (Get-FileHash $Path).Hash;
       $bkpPath = $Path + ".bak";
       $bkpHash = $null;
       if (Test-Path -PathType Leaf $bkpPath) {
           $bkpHash = (Get-FileHash $bkpPath).Hash;
       }
   
       if ($bkpHash -eq $DesiredHash) {
           return # already backed up
       }
   
       if ($curHash -ne $DesiredHash) {
           throw "$Path does not have the expected hash:`nExpected: $DesiredHash`nGot: $curHash`nWas the binary updated?";
       }
   
       Copy-Item $Path $bkpPath;
   }
   
   function PatchBinary {
       param (
           [string] $Path,
           [int] $Index,
           [byte] $Value
       )
       $data = [System.IO.File]::ReadAllBytes($Path)
       $data[$Index] = $Value;
       [System.IO.File]::WriteAllBytes($Path, $data)
   }
   
   $DLL_HASHES = @{
       "Off"     = "1370EE82E37F0E1AD71298E2B26A2E68183B61EC835F7936BBB5FC27397768C5"
       "Error"   = "907812BA7A9C9104C60851781BA2B68B65D3F476C63B0E6D75BC7A4F1B1E2455"
       "Warning" = "397FFCAF71EA1550D6E97ECCAF59C3368423BBDBAFA777BF25BF5EBA51512573"
       "Verbose" = "8040D68B22A95726FB0AD75BAC86BBBB74BCE45FDCA2902A7402E1DF6AB82E51"
   };
   $VALUES = @{
       "Off"     = [byte] 5
       "Error"   = [byte] 3
       "Warning" = [byte] 2
       "Verbose" = [byte] 1
   };
   $INDEX = 0x39FD9;
   
   $DLL_PATH = "debugAdapters\vsdbg\bin";
   $DLL_NAME = "CppDebug.dll";
   
   if (-not $VALUES.ContainsKey($Level)) {
       throw "Invalid level specified: $Level";
   }
   
   $extensionsDir = Join-Path $VsCodeDir "extensions";
   $debuggerBinDir = Join-Path $(FindCppToolsExtension -ExtensionsDir $extensionsDir) $DLL_PATH;
   $binaryPath = Join-Path $debuggerBinDir $DLL_NAME;
   
   BackupOriginalFile -Path $binaryPath -DesiredHash $DLL_HASHES["Off"];
   PatchBinary -Path $binaryPath -Index $INDEX -Value $VALUES[$Level];
   
   $newHash = (Get-FileHash $binaryPath).Hash;
   $expectedHash = $DLL_HASHES[$Level];
   if ($newHash -ne $expectedHash) {
       throw "Patched binary does not have expected hash`nExpected: $expectedHash`nGot: $newHash";
   }
   
   Write-Host -ForegroundColor Green "Set level to $Level";

   Footnotes

   1. There seems to be some mechanism to pass this value through environment variables as well, but it's disabled (I think). For this setting, you'd define Debugger_Level. However, in the function that loads this, the string gets unconditionally overwritten by an empty string, so it's never returned. ↩

   🎉React with 🎉4Reacted by Guus Waals, Jeremy Ong, Underdisc and Riley Labrecque
4. Bob Brown (bobbrow)

   added

   debugger

   enhancementImprovement to an existing featureImprovement to an existing feature

   on Feb 21, 2025
5. rlabrecque commented on Jul 3, 2025

   

   Riley Labrecque (rlabrecque)

   on Jul 3, 2025

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   Great script Nerixyz (@Nerixyz) ; hopefully easy enough for anyone else that needs to use this script to figure out, but I had to make a minor change to it:

   Before:

   $dirs = Get-ChildItem $ExtensionsDir -Filter "ms-vscode.cpptools*" -Directory;
   

   After:

   $dirs = Get-ChildItem $ExtensionsDir -Filter "ms-vscode.cpptools-1*" -Directory;
   

   Because it was also finding ms-vscode.cpptools-themes-2.0.0\

   Close VSCode before running it; then once you set it, the log messages were showing up in the Debug Console while running my application. Copy all that output over to a new vscode editor window or such then just search for your .natvis file.
6. sean-mcmanus commented on Jul 3, 2025

   

   Sean McManus (sean-mcmanus)

   on Jul 3, 2025

   Contributor

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   I think vsdbg is still being maintained but the VS debug team maintainers might not be aware of this bug. It's possible if someone reported the bug against VS on the Developer Community site then we could ship a fixed binary.
7. romasandu-gaijin commented on Dec 16, 2025

   

   romasandu-gaijin

   on Dec 16, 2025

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   Astounding that such a basic debugger usability feature is still missing in 2025. And the fix seems to be quite trivial too! Come on, Microsoft, if AI agents are so good, why don't you let one fix this bug?