Question

DPI imported and export tasks and functions can be declared anywhere a normal SystemVerilog task or function can be declared. Specifically, this means that they can be declared in module, program, interface, or generate declarative scope.

A context imported task or function executes in the context of the instantiated scope surrounding its declaration. This means that such tasks and functions can see other variables in that scope without qualification. As explained in Annex E.8.1, this should not be confused with the context of the task’s or function’s call site, which can actually be anywhere in the SystemVerilog design hierarchy. The context of an imported or exported task or function corresponds to the fully qualified name of the task or function, minus the task or function name itself.

Note that context is transitive through imported and export context tasks and functions declared in the same scope. That is, if an imported task or function is running in a certain context, and if it in turn calls an exported task or function that is available in the same context, the exported task or function can be called without any use of svSetScope(). For example, consider a SystemVerilog call to a native function f(), which in turn calls a native function g(). Now replace the native function f() with an equivalent imported context C function, f’(). The system shall behave identically regardless if f() or f’() is in the call chain above g(). g() has the proper execution context in both cases.