IZ95621: TEMPLATE ASSIGNMENT OPERATOR CALLS ITSELF

March 2011 PTF for XL C/C++ Enterprise Edition for AIX, V9.0
July 2011 PTF for XL C/C++ Enterprise Edition for AIX, V9.0
December 2011 PTF for XL C/C++ Enterprise Edition for AIX, V9.0
March 2012 PTF for XL C/C++ Enterprise Edition for AIX, V9.0

APAR status

• Closed as program error.

Error description

• template assignment operator calls itself recursively in the
  example below leading to segfault at runtime.
  
  
  ///////////////////// test.cpp //////////////////////
  
  template<typename First> struct Base
  {
    template<typename OtherFirst>
    First& operator=(const Base<OtherFirst>& other) { }
  
  inline First& operator=(const Base& other) {
     return operator=<First>(other); }
  };
  
  int main()
  {
   Base<int> a;
   a = Base<int>();
   return 0;
  }
  
  ////////////////// end of test.cpp //////////////////////
  
  $xlC test.cpp
  $./a.out
  Segmentation fault (core dumped)
  

Local fix

• N/A
  

Problem summary

• Assignment operator call with explicit template args may invoke
  incorrect function
  

Problem conclusion

• The problem is isolated to the FE and a fix has been dropped.
  

Temporary fix

Comments

APAR Information

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

  LI75770

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

Fix information

• Fixed component name

  XLC C++ AIX

• Fixed component ID

  5724S7100

Applicable component levels