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Pseudovariables in the Visual Studio debugger

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Pseudovariables are terms used to display certain information in a variable window or the QuickWatch dialog box. You can enter a pseudovariable the same way you would enter a normal variable. Pseudovariables are not variables, however, and do not correspond to variable names in your program.

Example

Suppose you are writing a native code application and want to see the number of handles allocated in your application. In the Watch window, you can enter the following pseudovariable in the Name column, then press Return to evaluate it:

$handles

In native code, you can use the pseudovariables shown in the following table:

Pseudovariable Function
$err Displays the last error value set with the function SetLastError. The value that is displayed represents what would be returned by the GetLastError function.

Use $err,hr to see the decoded form of this value. For example, if the last error was 3, the $err,hr would display ERROR_PATH_NOT_FOUND : The system cannot find the path specified.
$handles Displays the number of handles allocated in your application.
$vframe Displays the address of the current stack frame.
$tid Displays the thread ID for the current thread.
$env Displays the environment block in the string viewer.
$cmdline Displays the command line string that launched the program.
$pid Displays the process ID.
$ registername

or

@ registername		 Displays the contents of the register registername.

Normally, you can display register contents just by entering the register name. The only time you need to use this syntax is when the register name overloads a variable name. If the register name is the same as a variable name in the current scope, the debugger interprets the name as a variable name. That's when $registername or @registername comes in handy.
$clk Displays the time in clock cycles.
$user Displays a structure with account information for the account running the application. For security reasons, the password information is not displayed.
$exceptionstack Displays the stack trace of the current Windows Runtime exception. $ exceptionstack works only in UWP apps. $ exceptionstack is not supported for C++ and SEH exceptions
$returnvalue Displays the return value of a method.

In C# you can use the pseudovariables shown in the following table:

Pseudovariable Function
$exception Displays information on the last exception. If no exception has occurred, evaluating $exception displays an error message.

When the Exception Assistant is disabled, $exception is automatically added to the Locals window when an exception occurs.
$user Displays a structure with account information for the account running the application. For security reasons, the password information is not displayed.
$returnvalue Displays the return value of a .NET method.
$threadSmallObjectHeapBytes Displays the total number of bytes allocated in the small object heap by the current thread. (.NET 6+)
$threadUserOldHeapBytes Displays the total number of bytes allocated in the user old heap by the current thread. User Old Heap = Large Object Heap + Pinned Object Heap (.NET 6+)

In Visual Basic, you can use the pseudovariables shown in the following table:

Pseudovariable Function
$exception Displays information on the last exception. If no exception has occurred, evaluating $exception displays an error message.
$delete or $$delete Deletes an implicit variable that was created in the Immediate window. The syntax is $delete, variable or$delete, variable.
$objectids or $listobjectids Displays all active Object IDs as children of the specified expression. The syntax is $objectid, expression or$listobjectids, expression.
$ N # Displays object with Object ID equal to N.
$dynamic Displays the special Dynamic View node for an object that implements the IDynamicMetaObjectProvider. Interface. The syntax is $dynamic, object. This feature applies only to code that uses .NET Framework version 4 or later.

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