IV68564: EXCEPTION THROWN IN DESTRUCTOR NOT CAUGHT

XL C/C++ for AIX Fix Pack 4 (July 2015 PTF) for 13.1
XL C/C++ for AIX Fix Pack 5 (November 2015 PTF) for 13.1
XL C/C++ for AIX Fix Pack 6 (February 2016 PTF) for 13.1
XL C/C++ for AIX Fix Pack 7 (May 2016 PTF) for 13.1
XL C/C++ for AIX Fix Pack 8 (August 2016 PTF) for 13.1
XL C/C++ for AIX Fix Pack 9 (June 2017 PTF) for 13.1
XL C/C++ for AIX Fix Pack 10 (February 2018 PTF) for 13.1
XL C/C++ for AIX Fix Pack 11 (November 2018 PTF) for 13.1

APAR status

• Closed as program error.

Error description

• An exception thrown in an object destructor is not being caught
  inside the destructor even though it has a try/catch statement.
  
  Instead, the exception is cascaded back to a parent try/catch.
  The issue may be related to scoping around the object
  construction/destruction, as well as the inheritance structure
  of the class.
  
  
     === TEST CASE ===
  
  #include <stdio.h>
  
  struct Parent
  {
   ~Parent() {}
  };
  
  struct Child : Parent
  {
   typedef void (*func_ptr)();
   func_ptr passed_function;
  
   Child(func_ptr func) : passed_function(func) {}
  
   ~Child()
   {
    try { passed_function(); }
    catch (...) {}
   }
  };
  
  void my_exception_function()
  {
   throw 1;
  }
  
  int main(int, char*[])
  {
   try
   {
    {
     Child test(my_exception_function);
     printf("Test scope exception:  ");
    }
  
    printf("Good\n");
   }
   catch (...) { printf("Bad\n"); }
   return 0;
  }
  
  
  $ xlC test.cpp
  $ ./a.out
  Test scope exception:  Bad
  $
  

Local fix

• Modifications to the code may work around the issue:
  
  - make the destructor in the base class virtual
  - remove the base class destructor
  - remove the inheritance
  - remove the destructor declaration from the base class
  

Problem summary

• PROBLEM DESCRIPTION:
  Due to the extra lexical block in the try{} code, the compiler
  was not able to correctly determine the scope in which the
  destructors needed to be called.
  
  USERS AFFECTED:
  Users with nested exception handling with extra lexical block
  scope requiring destructors.
  

Problem conclusion

• A fix has been made to circumvent the issue.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  XL C/C++ FOR AI

• Fixed component ID

  5725C7200

Applicable component levels