Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

52 Chapter2
Controlling Asynchronous Devices Programmatically
MPE/iX System Intrinsics
illegal parameters to an intrinsic or does not have the capabilities
needed to execute an intrinsic. Such an error is called an abort error
and results in termination of the process.
Optional Capabilities
A number of system intrinsics can be used in a program only if you have
optional capabilities assigned to you. Optional capabilities are assigned
when your account is created, but can be altered by the System
Manager or Account Manager through use of appropriate MPE/iX
commands. See the MPE/iX Commands Reference Manual for more
information on how to alter the capabilities assigned to an account,
group or user.
If your program calls intrinsics which require optional capabilities you
must prepare the program with these capabilities specified. Such a
program can be run by users without the specific capabilities as long as
it resides in a group with the proper capabilities assigned.
None of the intrinsics discussed in this manual require optional
capabilities; however, if you intend to use NOWAIT I/O, you must have
specified the NOWAIT option in the FOPEN or HPFOPEN call used to
open the file. Specification of NOWAIT I/O requires that you have
Privileged Mode (PM) capability. Once NOWAIT I/O has been specified
you can control completion operations for I/O requests by calling the
IOWAIT or IODONTWAIT intrinsics, as described in Chapter 8,
“Intrinsics Reference.”