This avoids any possible strange behavior with calling Marinetti in P8 mode. It also ensures that I/O operations in P8 mode will give an error, but not terminate the connection: it will still be alive when we get back to GS/OS, unless the server has killed it due to inactivity (which is quite possible).
This occurred because a global with structure type was declared without the structure definition in scope. ORCA/C allows this, and just treats the struct variable as having size 0. As a result, it effectively shares the storage of whatever comes after it in the OMF file, leading to memory trashing.
Stephen Heumann