These were implemented as returning nothing (void), and passing an
invalid operation value would trigger an assertion failure. The IEEE
standards define them as returning 1 on success and 0 on failure.
vpi_sim_control() is the name used in Verilog-AMS. Strictly speaking
it should return a bool, but to avoid polluting the namespace by
including stdbool.h, we return a PLI_INT32. As C is a weakly typed
language, this should make no practical difference.
__CYGWIN32__ is not defined when building with the 64-bit Cygwin
toolchain. According to the Cygwin FAQ, __CYGWIN__ has been defined
since 1998, so this should still work for users on 32-bit systems.
The old scheme of linking the VPI modules with the vvp exports meant they
did not work when loaded by the compiler. Instead, let each client create
a jump table for the VPI routines and pass that to each VPI module as it
is loaded.
Martin Whitaker
mole99