General facts about C++ to PL/I ILC

ILC between C++ and Enterprise PL/I for z/OS® is discussed in the IBM Enterprise PL/I for z/OS library.
Language Environment does not support passing return codes between PL/I and C++ routines in an ILC application.
PL/I Multitasking Facility (MTF) does not support C++.
A C++ NULL is X'00000000'; a PL/I NULL is X'FF000000'; a PL/I SYSNULL is X'00000000'. Comparisons against a NULL value and other uses of the NULL value must therefore be done with care.
There is no ILC support between AMODE 31 and AMODE 64 applications. PL/I does not support AMODE 64.