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

258 Chapter9
Intrinsics Reference (cont)
HPFOPEN
• Each optional parameter specified in the file equation string
option
(Item# = 52) is treated as if it were the equivalent
itemnum/item pair when determining precedence.
Parameters
filenum 32-bit signed integer by reference
(required)
Returns a file number used to identify the opened file in
subsequent intrinsic calls.
status 32-bit signed integer by reference
(optional)
Returns the status of the HPFOPEN call. If no errors or
warnings are encountered,
status returns 32 bits of
zero. If errors or warnings are encountered,
status is
interpreted as two 16-bit fields. The status parameter
is used in place of error checking routines that call
FCHECK. Such routines are not useful with
HPFOPEN.
Bits (0:16) comprise
status.info . A negative value
indicates an error condition, and a positive value
indicates a warning condition. See the MPE/iX
Intrinsics Reference Manual for a list of possible values.
Bits (16:16) comprise
status.subsys . The value
represented by these bits defines the subsystem that
set the status information. The File System
identification number is 143.
CAUTION Since HPFOPEN can return information on the success of its execution
in the status parameter, it is good programming practice to specify this
parameter and check its value after the intrinsic call. If an error or
warning condition is encountered and you did not specify the status
parameter, HPFOPEN causes the calling process to abort.
filenum 32-bit signed integer by value (optional)
The item number of an HPFOPEN option, as defined in
the
itemnum/item summary that follows.
item type varies by reference (optional)
Passes and/or returns the HPFOPEN option indicated
by the corresponding itemnum parameter, as described
in the itemnum/item summary that follows.