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HPDEVCONTROL
NM callable only.
Provides access to specified peripheral functionality without the device
being opened. Allows access to device utilities; not for general control
(for example, reading or writing). Nonshareable device (ND) capability
is required.
Syntax
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| |
| I32 CA I32 I32 |
| HPDEVCONTROL(status,ldev,itemnum,item);|
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Parameters
status 32-bit integer (required)
Returns the status of the HPDEVCONTROL 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
represents the subsystem that sets the status
information. There is no specific subsystem
identifier for HPDEVCONTROL.
ldev character array (required)
Passes the LDEV number of the device to be
accessed. This parameter is a 200-character packed
array.
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NOTE This parameter must be delimited with a
printable, non-numeric character and must be
zero left-filled:
"00000007" or
a00000007a
Whatever delimiter begins the parameter must
also end the parameter. The delimiter itself
must not appear within the parameter.
a0000a007a will cause an error because a
appears within the parameter.
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NOTE The LDEV parameter must be defined as 200
characters in the calling program. However,
because logical device numbers are currently
limited in size to 10 bytes only the leftmost
10 bytes of the array is used. For this
reason, the ldev should be loaded into the
leftmost 10 bytes of the 200-character array
before the call is made.
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It also may be important to understand that the
system converts this parameter to a pointer before
passing it to the intrinsic. It should not be
coded as a pointer in the calling program, however.
itemnum 32-bit integer (required)
Specifies which operation is to be performed (refer
to Table 4-18 ).
item 32-bit integer (required)
Table 4-18. HPDEVCONTROL Itemnum/Item Values
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| | | |
| Itemnum | Mnemonic | Item Description |
| | | |
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| | | |
| 100 | I32 | Load Media: |
| | | |
| | | Attempts to load the media (tape devices only). |
| | | |
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| | | |
| 101 | I32 | Online: |
| | | |
| | | Programmatically places the peripheral online (tape devices only). |
| | | |
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This intrinsic is not supported for the following devices: 7974, 7976
and 7978A. If a call is made against one of these devices an error is
returned. Only item number 100 is supported for the 7978B.
NOTE A call with an item number 100 (load) to a device which is already
loaded is acceptable (produces no harmful result). However a tape
device would go offline (only an HPIB DAT drive would not go
offline). It is recommended that this intrinsic be called with
item 100 followed by 101 whenever it is used for a tape device.
Related Information
Intrinsics None
Commands None
Manuals None