cpp_extensions

Controls language extensions to ISO/IEC 14882:2003 C++.

#pragma cpp_extensions on | off | reset

If you enable this pragma, you can use the following extensions to the ISO/IEC 14882:2003 C++ standard that would otherwise be invalid:

• Anonymous struct & union objects. Example of Anonymous struct & union Objects shows an example.
  Listing 1. Example of Anonymous struct & union Objects

#pragma cpp_extensions on
void func()
{
  union {
    long  hilo;
    struct { short hi, lo; }; //  anonymous struct
  };
  hi=0x1234; 
  lo=0x5678;  //  hilo==0x12345678      
}

• Unqualified pointer to a member function. Example of an Unqualified Pointer to a Member Function shows an example.
  Listing 2. Example of an Unqualified Pointer to a Member Function

#pragma cpp_extensions on
struct RecA { void f(); }
void RecA::f()
{
  void (RecA::*ptmf1)() = &RecA::f; // ALWAYS OK

  void (RecA::*ptmf2)() = f; // OK if you enable cpp_extensions.
}

• Inclusion of const data in precompiled headers.

By default, this pragma is disabled.