Example: Effect of Forward Declarations on the Data Model

In the following figure, struct Foo does not use the P128 data model in effect at the time of its forward-declaration. Instead, struct Foo uses the LLP64 data model in effect at the time struct Foo is fully declared.

Figure 1. Example of a Forward Declaration Based on the LLP64 Data Model

   #pragma datamodel(P128) 
   struct Foo;  //forward declaration
   #pragma datamodel(LLP64)
   struct Foo {
      char* string; // this pointer is 8-byte because LLP64 datamodel
                    // was in effect for the struct definition.
   };
   #pragma datamodel(pop)
   #pragma datamodel(pop)