- numfiles
integer by value (required)
Passes the number of files (number of files -1) whose bits will be
checked by HPSELECT.
Note that this parameter does not represent the number of files where
a bit in one of the masks is being set. It represents the highest file
number (minus 1) that will be examined by HPSELECT.
- readmask
character array by reference (optional)
Specifies which file numbers will be examined to see if the file that is
ready for reading should be passed. The least significant bit of each
32-bit word represents the lowest file number in the word. The first
word contains the bits for the first 32 files. Subsequent words contain
the bits for additional groups of 32 files.
For each file number less than numfiles, the corresponding bit
in the mask is set at return if the bit was set at entry and the file is
ready for reading.
Bits representing file numbers greater than numfiles (minus 1)
are ignored. The buffer containing the bit mask only needs to be as large
as the number of 32-bit words required to contain the bits for
numfiles files.
If a timeout is specified and the time limit has elapsed, the mask is
cleared on return.
Default: No files are checked for reading.
- writemask
character array by reference (optional)
Specifies which file numbers are to be examined to see if the
file is ready for writing. The last significant bit of each
32-bit word represents the lowest file number in the word. The
first word contains the bits for the first 32 files. Subsequent words
contain the bits for additional groups of 32 files.
For each file number less than numfiles, the corresponding bit
in the mask is set at return if the bit was set at entry and the file is
ready for writing.
Bits representing file numbers greater than numfiles (minus 1)
are ignored. The buffer containing the bit mask only needs to be as large
as the number of 32-bit words required to contain the bits for
numfiles files.
If a timeout is specified and the time limit has elapsed, the mask is
cleared on return.
Default: No files are checked for writing.
- exceptionmask
character array by reference (optional)
Specifies which file numbers are to be examined to see if the
file has detected an exception condition. The last significant bit of each
32-bit word represents the lowest file number in the word. The
first word contains the bits for the first 32 files. Subsequent words
contain the bits for additional groups of 32 files.
For each file number less than numfiles, the corresponding bit
in the mask is set at return if the bit was set at entry and the file has
detected an exception condition.
Bits representing file numbers greater than numfiles (minus 1)
are ignored. The buffer containing the bit mask only needs to be as large
as the number of 32-bit words required to contain the bits for
numfiles files.
If a timeout is specified and the time limit has elapsed, the mask is
cleared on return.
Default: No files are checked for exception conditions.
- timeout
record by reference (optional)
Specifies a maximum interval to wait for the selection to complete. If a
timeout value of 0 is supplied, HPSELECT checks for the specified
conditions, sets the return mask, and returns without blocking even if
none of the specified conditions are true. If a timeout value is not
specified, HPSELECT waits until an event causes one of the masks to be
returned with a non-zero value.
The timeout value is specified by a 64-bit record containing the
following two fields:
- 32-bit unsigned integer =
seconds
- 32-bit integer =
microseconds
Values up to 2**32 seconds can be specified.
Default: HPSELECT blocks until one of the specified conditions
is true.
- status
32-bit integer by reference (optional)
Returns the status of the HPSELECT 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.
Bits (0:16) comprise status.info. A negative value indicates an error
condition, and a positive value indicates a warning condition. Refer to the
MPE/iX Error Message Manual Volumes 1, 2 and 3 (32650-90066, 32650-90152, and 32650-90368) for a description of its value.
Bits (16:16) comprise status.subsys. The value represented by these
bits defines the subsystem that set the status information. The subsystem
identifier for HPSELECT is 143.
Possible error values of status.info are:
