LI76534: ISSUE WITH SIZEOF FOR TEMPLATES

XL C/C++ for Linux Fix Pack 8 (January 2014 Update) for 10.1
January 2012 Update for XL C/C++ for Linux, V10.1
July 2012 Update for XL C/C++ for Linux, V10.1

APAR status

• Closed as program error.

Error description

• The test case below produces an incorrect output when
  calculating the sizeof of a struct with templates present:
  
  ===== COMPILE COMMAND:
  xlC test.cpp
  
  ===== TESTCASE:
  $cat test.cpp
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  template <int SZ> class Arr { int arr[SZ];};
  class C
  {
          public:
          struct TestIt { char Y[100]; };
    Arr <3> mem; // NOTICE THIS LINE
    enum { SizeOfTest = sizeof(TestIt) };
  
  };
  
  int main (int argc, char** argv)
  {
          C c;
    printf("%d\n",C::SizeOfTest);
  }
  $
  
  
  
  ===== ACTUAL OUTPUT:
  $xlC test.cpp
  $ ./a.out
  1
  $
  
  
  ===== EXPECTED OUTPUT:
  $xlC test.cpp
  $ ./a.out
  100
  $
  

Local fix

• n/a
  

Problem summary

• USERS AFFECTED:
  Users of sizeof with a member of a template class may be
  affected by this issue.
  
  PROBLEM DESCRIPTION:
  Sizeof() may not work correctly for some cases involving
  template classes.
  

Problem conclusion

• The compiler has been fixed to resolve the sizeof() issue for
  the reported test case.
  

Temporary fix

Comments

APAR Information

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

  IV01078

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

Fix information

• Fixed component name

  XL C/C++ RHEL52

• Fixed component ID

  5724U8310

Applicable component levels

• RA10 PSN IV01078

     UP06/09/13