How to reproduce:
>>>code
int32 n = 0xF71B0000;
int32 n1 = pac_swap(n);
code<<<
n1 becomes 0xFFFFFFF7 instead of 0x00001BF7
Reason: Undefined behaviour after bit shift operation because of
negative value of the argument. See C++ standard (2011) 5.8.2 (Shift
operators).
This helps ensure the availability of PRI* macros from .pac files,
which cannot create this definition themselves since the inclusion
of binpac.h is hardcoded to be placed very early in the generated
code and already includes inttypes.h itself.
The code generated for types w/ &refcount will subclass RefCount and
Unref definitely deletes via a pointer to that base class so it needs a
virtual dtor.
