Catching "Stack Overflow" exceptions in recursive C++ functions

Question

Is it possible to catch a stack overflow exception in a recursive C++ function? If so, how?

so what will happen in this case

void doWork()
{

     try() {

     doWork();    
     }


     catch( ... )  {

     doWork();    
     }
}  

I am not looking for an answer to specific OS. Just in general

Answer 1

It's not an exception per se, but if you just want to be able to limit your stack usage to a fixed amount, you could do something like this:

#include <stdio.h>

// These will be set at the top of main()
static char * _topOfStack;
static int _maxAllowedStackUsage;

int GetCurrentStackSize()
{
   char localVar;
   int curStackSize = (&localVar)-_topOfStack;
   if (curStackSize < 0) curStackSize = -curStackSize;  // in case the stack is growing down
   return curStackSize;
}

void MyRecursiveFunction()
{
   int curStackSize = GetCurrentStackSize();
   printf("MyRecursiveFunction:  curStackSize=%i\n", curStackSize);

   if (curStackSize < _maxAllowedStackUsage) MyRecursiveFunction();
   else
   {
      printf("    Can't recurse any more, the stack is too big!\n");
   }
}

int main(int, char **)
{
   char topOfStack;
   _topOfStack = &topOfStack;
   _maxAllowedStackUsage = 4096;  // or whatever amount you feel comfortable allowing

   MyRecursiveFunction();
   return 0;
}

Answer 2

There isn't a portable way. However, there are a few nonportable solutions.

First, as others have mentioned, Windows provides a nonstandard __try and __except framework called Structured Exeption Handling (your specific answer is in the Knowledge Base).

Second, alloca -- if implemented correctly -- can tell you if the stack is about to overflow:

bool probe_stack(size_t needed_stack_frame_size)
{
    return NULL != alloca(needed_stack_frame_size);
};

I like this approach, because at the end of probe_stack, the memory alloca allocated is released and available for your use. Unfortunately only a few operating systems implement alloca correctly. alloca never returns NULL on most operating systems, letting you discover that the stack has overflown with a spectacular crash.

Third, UNIX-like systems often have a header called ucontext.h with functions to set the size of the stack (or, actually, to chain several stacks together). You can keep track of where you are on the stack, and determine if you're about to overflow. Windows comes with similar abilities a la CreateFiber.

---

As of Windows 8, Windows has a function specifically for this (GetCurrentThreadStackLimits)