C catch a stack overflow exception

Question

I have a recursive call to a method that throws a stack overflow exception  The first call is surrounded by a try catch block but the exception is not caught    Does the stack overflow exception behave in a special way  Can I catch handle the exception properly   Not sure if relevant  but additional information     the exception is not thrown in the main thread  the object where the code is throwing the exception is manually loaded by Assembly LoadFrom      CreateInstance

User · Answer

From the MSDN page on StackOverflowExceptions:

In prior versions of the .NET Framework, your application could catch a StackOverflowException object (for example, to recover from unbounded recursion). However, that practice is currently discouraged because significant additional code is required to reliably catch a stack overflow exception and continue program execution.

Starting with the .NET Framework version 2.0, a StackOverflowException object cannot be caught by a try-catch block and the corresponding process is terminated by default. Consequently, users are advised to write their code to detect and prevent a stack overflow. For example, if your application depends on recursion, use a counter or a state condition to terminate the recursive loop. Note that an application that hosts the common language runtime (CLR) can specify that the CLR unload the application domain where the stack overflow exception occurs and let the corresponding process continue. For more information, see ICLRPolicyManager Interface and Hosting the Common Language Runtime.

User · Answer

You can t as most of the posts are explaining  let me add another area   On many websites you will find people saying that the way to avoid this is using a different AppDomain so if this happens the domain will be unloaded  That is absolutely wrong  unless you host your CLR  as the default behavior of the CLR will raise a KillProcess event  bringing down your default AppDomain

User · Answer

You can t  The CLR won t let you  A stack overflow is a fatal error and can t be recovered from

User · Answer

The right way is to fix the overflow  but      You can give yourself a bigger stack -  using System Threading  Thread T   new Thread threadDelegate  stackSizeInBytes   T Start      You can use System Diagnostics StackTrace FrameCount property to count the frames you ve used and throw your own exception when a frame limit is reached   Or  you can calculate the size of the stack remaining and throw your own exception when it falls below a threshold -  class Program       static int n      static int topOfStack      const int stackSize   1000000     Default          The func is 76 bytes  but we need space to unwind the exception      const int spaceRequired   18 1024        unsafe static void Main string   args                int var          topOfStack    int  amp var           n 0          recurse               unsafe static void recurse                 int remaining          remaining   stackSize -  topOfStack -  int  amp remaining           if  remaining  lt  spaceRequired              throw new Exception  Cheese            n            recurse              Just catch the Cheese

User · Answer

As mentioned above several times  it s not possible to catch a StackOverflowException that was raised by the System due to corrupted process-state  But there s a way to notice the exception as an event      http   msdn microsoft com en-us library system appdomain unhandledexception aspx      Starting with the  NET Framework version 4  this event is not raised for exceptions that corrupt the state of the process  such as stack overflows or access violations  unless the event handler is security-critical and has the HandleProcessCorruptedStateExceptionsAttribute attribute    Nevertheless your application will terminate after exiting the event-function  a VERY dirty workaround  was to restart the app within this event haha  havn t done so and never will do   But it s good enough for logging      In the  NET Framework versions 1 0 and 1 1  an unhandled exception that occurs in a thread other than the main application thread is caught by the runtime and therefore does not cause the application to terminate  Thus  it is possible for the UnhandledException event to be raised without the application terminating  Starting with the  NET Framework version 2 0  this backstop for unhandled exceptions in child threads was removed  because the cumulative effect of such silent failures included performance degradation  corrupted data  and lockups  all of which were difficult to debug  For more information  including a list of cases in which the runtime does not terminate  see Exceptions in Managed Threads

User · Answer

It s impossible  and for a good reason  for one  think about all those catch Exception    around     If you want to continue execution after stack overflow  run dangerous code in a different AppDomain  CLR policies can be set to terminate current AppDomain on overflow without affecting original domain

User · Answer

Starting with 2 0 a StackOverflow Exception can only be caught in the following circumstances   The CLR is being run in a hosted environment  where the host specifically allows for StackOverflow exceptions to be handled The stackoverflow exception is thrown by user code and not due to an actual stack overflow situation  Reference     quot hosted environment quot  as in  quot my code hosts CLR and I configure CLR s options quot  and not  quot my code runs on shared hosting quot

User · Answer

Yes from CLR 2 0 stack overflow is considered a non-recoverable situation  So the runtime still shut down the process    For details please see the documentation http   msdn microsoft com en-us library system stackoverflowexception aspx

User · Answer

As several users have already said  you can t catch the exception   However  if you re struggling to find out where it s happening  you may want to configure visual studio to break when it s thrown   To do that  you need to open Exception Settings from the  Debug  menu   In older versions of Visual Studio  this is at  Debug  -  Exceptions   in newer versions  it s at  Debug  -  Windows  -  Exception Settings    Once you have the settings open  expand  Common Language Runtime Exceptions   expand  System   scroll down and check  System StackOverflowException    Then you can look at the call stack and look for the repeating pattern of calls   That should give you an idea of where to look to fix the code that s causing the stack overflow

[c#] C# catch a stack overflow exception

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