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OpenVMS System Services Reference Manual
$IO_PERFORMW (Alpha Only)
On Alpha systems, starts a Fast I/O operation. The $IO_PERFORMW service
completes synchronously; that is, it returns to the caller after
performing the Fast I/O operation.
In all other respects, $IO_PERFORMW is identical to $IO_PERFORM. For
all other information about the IO_PERFORMW service, refer to the
description of $IO_PERFORM in this manual.
Format
SYS$IO_PERFORMW fandle ,chan ,iosadr ,bufadr ,buflen ,devdata
C Prototype
int sys$io_performw (unsigned __int64 fandl, unsigned short int chan,
struct _iosa *iosadr, void *bufadr, unsigned __int64 buflen, unsigned
__int64 devdata);
$IO_SETUP (Alpha Only)
On Alpha systems, allocates resources for Fast I/O.
This service accepts 64-bit addresses.
Format
SYS$IO_SETUP func ,bufobj ,iosobj ,astadr ,flags ,return_fandle
C Prototype
int sys$io_setup (unsigned int func, struct _generic_64 *bufobj, struct
_generic_64 *iosobj, void (*astadr)(struct _iosa *), unsigned int
flags, unsigned __int64 *return_fandle);
Arguments
func
| OpenVMS usage: |
function_code |
| type: |
longword |
| access: |
read only |
| mechanism: |
by value |
I/O function code. Must be one of the following:
- IO$_READVBLK
- IO$_WRITEVBLK
- IO$_READLBLK
- IO$_WRITELBLK
Various function modifiers are supported, depending on the device and
driver. Disk drivers support IO$M_NOVCACHE and IO$M_DATACHECK. Some
tape devices support IO$M_REVERSE. Illegal modifiers are detected by
the $IO_PERFORM(W) service.
bufobj
| OpenVMS usage: |
buffer object |
| type: |
quadword (unsigned) |
| access: |
read only |
| mechanism: |
by 32- or 64-bit reference |
Handle describing the buffer object that contains the user's buffer.
This identifier cannot be 0.
iosobj
| OpenVMS usage: |
object handle |
| type: |
vector longword (unsigned) |
| access: |
read only |
| mechanism: |
by 32- or 64-bit reference |
Buffer object handle describing the buffer object that contains the I/O
Status Area (IOSA). This might or might not be the same identifier as
the bufobj argument. This identifier cannot be 0.
astadr
| OpenVMS usage: |
ast_procedure |
| type: |
procedure value |
| access: |
read only |
| mechanism: |
by 32- or 64-bit reference |
Completion AST routine address (0, if none). There is no AST
parameter argument. When the AST routine is called, the AST
parameter will be the address of the IOSA for the operation.
Applications can store data in the IOSA at offset IOSA$IH_CONTEXT.
flags
| OpenVMS usage: |
mask_longword |
| type: |
64-bit integer (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Flag mask. The flags argument is a bit vector in which
each bit corresponds to a flag. Flags are defined in the module IOSADEF.
The following table describes the flags that are valid for the
$IO_SETUP service:
| Flag |
Description |
|
FIO$M_EXPEDITE
|
This is a
high priority I/O; that is, it is to be given preferential
treatment by the I/O subsystem. Use of this bit requires ALTPRI or
PHY_IO privilege.
|
|
FIO$M_AST_NOFLOAT
|
The AST procedure does not use, or call any procedure that uses, any
floating-point registers. This is a performance option. If set, AST
delivery will neither save nor restore floating-point registers.
Caution: Use of floating-point registers when FIO$M_AST_NOFLOAT has
been specified can cause unpredictable, difficult to detect, error
conditions.
|
All other bits in the flags argument are reserved for
future use by Compaq and should be specified as 0.
return_fandle
| OpenVMS usage: |
fandle |
| type: |
64-bit integer (unsigned) |
| access: |
write only |
| mechanism: |
by 32- or 64-bit reference |
Address of an aligned quadword to receive the fandle for this I/O
operation.
Description
The Set Up Fast I/O system service allocates and initializes a number
of internal objects based on the parameters supplied. Because these
objects are then ready for use when a subsequent $IO_PERFORM or
$IO_PERFORMW is issued, the I/O operation will require less CPU time
and fewer multiprocessor steps.
Required Privileges
If you use the flags argument FIO$M_EXPEDITE, a
process must have ALTPRI or PHY_IO privilege.
Required Quota
Byte count
Related Services
$IO_CLEANUP, $IO_PERFORM(W)
Condition Values Returned
|
SS$_NORMAL
|
The service completed successfully.
|
|
SS$_ACCVIO
|
The fandle does not have 8 bytes of writability, or the two buffer
objects do not have 8 bytes of readability each.
|
|
SS$_INSFMEM
|
There is no pool available from which to create a fandle vector, or the
fandle vector is already full and an attempted expansion failed.
|
|
SS$_ILLIOFUNC
|
The function code is not valid.
|
|
SS$_ILLMODIFIER
|
The I/O function modifier is not permitted.
|
|
SS$_UNALIGNED
|
The I/O Status Area (IOSA) or data buffer is not aligned on a quadword
boundary.
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$LCKPAG
Locks a page or range of pages in memory. The specified virtual pages
are forced into the working set and then locked in memory. A locked
page is not swapped out of memory if the working set of the process is
swapped out. These pages are not candidates for page replacement and in
this sense are locked in the working set as well.
Format
SYS$LCKPAG inadr ,[retadr] ,[acmode]
C Prototype
int sys$lckpag (struct _va_range *inadr, struct _va_range *retadr,
unsigned int acmode);
Arguments
inadr
| OpenVMS usage: |
address_range |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by reference |
Starting and ending virtual addresses of the range of pages to be
locked. The inadr argument is the address of a
2-longword array containing, in order, the starting and ending process
virtual addresses. Only the virtual page number portion of each virtual
address is used; the low-order byte-within-page bits are ignored.
On VAX systems, if the starting and ending virtual addresses are the
same, a single page is locked.
retadr
| OpenVMS usage: |
address_range |
| type: |
longword (unsigned) |
| access: |
write only |
| mechanism: |
by reference |
Starting and ending process virtual addresses of the pages that $LCKPAG
actually locked. The retadr argument is the address of
a 2-longword array containing, in order, the starting and ending
process virtual addresses.
acmode
| OpenVMS usage: |
access_mode |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Access mode to be associated with the pages to be locked. The
acmode argument is a longword containing the access
mode. The $PSLDEF macro defines the four access modes.
The most privileged access mode used is the access mode of the caller.
For the $LCKPAG service to complete successfully, the resultant access
mode must be equal to or more privileged than the access mode already
associated with the pages to be locked.
Description
The Lock Pages in Memory service locks a page or range of pages in
memory. The specified virtual pages are forced into the working set and
then locked in memory. A locked page is not swapped out of memory if
the working set of the process is swapped out. These pages are not
candidates for page replacement and in this sense are locked in the
working set as well.
If more than one page is being locked and you need to determine
specifically which pages were previously locked, the pages should be
locked one at a time.
If an error occurs while the $LCKPAG service is locking pages, the
return array, if requested, indicates the pages that were successfully
locked before the error occurred. If no pages are locked, both
longwords in the return address array contain the value --1.
On Alpha systems, if you are attempting to lock executable code, you
should issue multiple $LCKPAG calls: one to lock the code pages and
others to lock the linkage section references into these pages.
Required Access or Privileges
The calling process must have PSWAPM privilege to lock pages into
memory.
Required Quota
None
Related Services
You can unlock pages locked in memory with the Unlock Pages from Memory
($ULKPAG) service. Locked pages are automatically unlocked at image
exit.
For more information, refer to the chapter on memory management in the
OpenVMS Programming Concepts Manual.
Condition Values Returned
|
SS$_WASCLR
|
The service completed successfully. All of the specified pages were
previously unlocked.
|
|
SS$_WASSET
|
The service completed successfully. At least one of the specified pages
was previously locked.
|
|
SS$_ACCVIO
|
The input array cannot be read; the output array cannot be written; the
page in the specified range is inaccessible or nonexistent; or an
attempt to lock pages was made by a caller whose access mode is less
privileged than the access mode associated with the pages.
|
|
SS$_LCKPAGFUL
|
The system-defined maximum limit on the number of pages that can be
locked in memory has been reached.
|
|
SS$_LDWSETFUL
|
The locked working set is full. If any more pages are locked, not
enough dynamic pages will be available to continue execution.
|
|
SS$_NOPRIV
|
The process does not have the privilege to lock pages in memory.
|
|
SS$_PAGOWNVIO
|
The pages could not be locked because the access mode associated with
the call to $LCKPAG was less privileged than the access mode associated
with the pages that were to be locked.
|
$LCKPAG_64 (Alpha Only)
On Alpha systems, locks a range of pages in memory. The specified
virtual pages are forced into the working set and then locked in
memory. A locked page is not swapped out of memory if the working set
of the process is swapped out. These pages are not candidates for page
replacement and, in this sense, are locked in the working set as well.
This service accepts 64-bit addresses.
Format
SYS$LCKPAG_64 start_va_64 ,length_64 ,acmode ,return_va_64
,return_length_64
C Prototype
int sys$lckpag_64 (void *start_va_64, unsigned __int64 length_64,
unsigned int acmode, void *(*(return_va_64)), unsigned __int64
*return_length_64);
Arguments
start_va_64
| OpenVMS usage: |
address |
| type: |
quadword address |
| access: |
read only |
| mechanism: |
by value |
The starting virtual address of the pages to be locked. The specified
virtual address will be rounded down to a CPU-specific page boundary.
length_64
| OpenVMS usage: |
byte count |
| type: |
quadword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Length of the virtual address space to be locked. The specified length
will be rounded up to a CPU-specific page boundary so that it includes
all CPU-specific pages in the requested range.
acmode
| OpenVMS usage: |
access_mode |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Access mode associated with the pages to be locked. The
acmode argument is a longword containing the access
mode.
The $PSLDEF macro in STARLET.MLB and the file PSLDEF.H in
SYS$STARLET_C.TLB define the following symbols and their values for the
four access modes:
| Value |
Symbolic Name |
Access Mode |
|
0
|
PSL$C_KERNEL
|
Kernel
|
|
1
|
PSL$C_EXEC
|
Executive
|
|
2
|
PSL$C_SUPER
|
Supervisor
|
|
3
|
PSL$C_USER
|
User
|
The most privileged access mode used is the access mode of the caller.
For the $LCKPAG_64 service to complete successfully, the resultant
access mode must be equal to or more privileged than the access mode
already associated with the pages to be locked.
return_va_64
| OpenVMS usage: |
address |
| type: |
quadword address |
| access: |
write only |
| mechanism: |
by 32- or 64-bit reference |
The lowest process virtual address of the pages locked in memory. The
return_va_64 argument is the 32- or 64-bit virtual
address of a naturally aligned quadword into which the service returns
the virtual address.
return_length_64
| OpenVMS usage: |
byte count |
| type: |
quadword (unsigned) |
| access: |
write only |
| mechanism: |
by 32- or 64-bit reference |
The 32- or 64-bit virtual address of a naturally aligned quadword into
which the service returns the length of the virtual address range
locked in bytes.
Description
The Lock Pages in Memory service locks a range of pages in memory. The
specified virtual pages are forced into the working set and then locked
in memory. A locked page is not swapped out of memory if the working
set of the process is swapped out. These pages are not candidates for
page replacement and, in this sense, are locked in the working set as
well.
If the condition value SS$_ACCVIO is returned by this service, a value
cannot be returned in the memory locations pointed to by the
return_va_64 and return_length_64
arguments. If a condition value other than SS$_ACCVIO is returned, the
returned address and returned length indicate the pages that were
successfully locked before the error occurred. If no pages were locked,
the return_va_64 argument will contain the value -1,
and a value cannot be returned in the memory location pointed
to by the return_length_64 argument.
Required Privileges
A process must have PSWAPM privilege to call the $LCKPAG_64 service.
Required Quota
None
Related Services
$LCKPAG, $ULKPAG, $ULKPAG_64
Condition Values Returned
|
SS$_WASCLR
|
The service completed successfully. All of the specified pages were
previously unlocked.
|
|
SS$_WASSET
|
The service completed successfully. At least one of the specified pages
was previously locked in the working set.
|
|
SS$_ACCVIO
|
The
return_va_64 argument or the
return_length_64 argument cannot be written by the
caller, or an attempt was made to lock pages by a caller whose access
mode is less privileged than the access mode associated with the pages.
|
|
SS$_LCKPAGFUL
|
The system-defined maximum limit on the number of pages that can be
locked in memory has been reached.
|
|
SS$_LKWSETFUL
|
The locked working set is full. If any more pages are locked, not
enough dynamic pages will be available to continue execution.
|
|
SS$_NOPSWAPM
|
The process does not have the privilege to lock pages in memory.
|
|
SS$_PAGOWNVIO
|
The pages could not be locked because the access mode associated with
the call to $LCKPAG_64 was less privileged than the access mode
associated with the pages that were to be locked.
|
$LKWSET
Locks a range of pages in the working set; if the pages are not already
in the working set, it brings them in and locks them. A page locked in
the working set does not become a candidate for replacement.
Format
SYS$LKWSET inadr ,[retadr] ,[acmode]
C Prototype
int sys$lkwset ( struct _va_range *inadr, struct _va_range *retadr,
unsigned int acmode);
Arguments
inadr
| OpenVMS usage: |
address_range |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by reference |
Starting and ending virtual addresses of the range of pages to be
locked in the working set. The inadr argument is the
address of a 2-longword array containing, in order, the starting and
ending process virtual addresses. Only the virtual page number portion
of each virtual address is used; the low-order byte-within-page bits
are ignored.
On VAX systems, if the starting and ending virtual addresses are the
same, a single page is locked.
retadr
| OpenVMS usage: |
address_range |
| type: |
longword (unsigned) |
| access: |
write only |
| mechanism: |
by reference |
Starting and ending process virtual addresses of the range of pages
actually locked by $LCKWSET. The retadr argument is
the address of a 2-longword array containing, in order, the starting
and ending process virtual addresses.
acmode
| OpenVMS usage: |
access_mode |
| type: |
longword (unsigned) |
| access: |
read only |
| mechanism: |
by value |
Access mode to be associated with the pages to be locked. The
acmode argument is a longword containing the access
mode. The $PSLDEF macro defines the four access modes.
The most privileged access mode used is the access mode of the caller.
For the $LKWSET service to complete successfully, the resultant access
mode must be equal to or more privileged than the access mode already
associated with the pages to be locked.
Description
The Lock Pages in Working Set service locks a range of pages in the
working set; if the pages are not already in the working set, it brings
them in and locks them. A page locked in the working set does not
become a candidate for replacement.
If more than one page is being locked and you need to determine
specifically which pages were previously locked, the pages should be
locked one at a time.
If an error occurs while the $LKWSET service is locking pages, the
return array, if requested, indicates the pages that were successfully
locked before the error occurred. If no pages are locked, both
longwords in the return address array contain the value --1.
Global pages with write access cannot be locked into the working set.
On Alpha systems, if you are attempting to lock executable code, you
should issue multiple $LKWSET calls: one to lock the code pages and
others to lock the linkage section references into these pages.
Required Access or Privileges
None
Required Quota
None
Related Services
You can unlock pages locked in the working set with the Unlock Page
from Working Set ($ULWSET) service.
For more information, refer to the chapter on memory management in the
OpenVMS Programming Concepts Manual.
Condition Values Returned
|
SS$_WASCLR
|
The service completed successfully. All of the specified pages were
previously unlocked.
|
|
SS$_WASSET
|
The service completed successfully. At least one of the specified pages
was previously locked in the working set.
|
|
SS$_ACCVIO
|
The input address array cannot be read; the output address array cannot
be written; a page in the specified range is inaccessible or
nonexistent; or an attempt was made to lock pages by a caller whose
access mode is less privileged than the access mode associated with the
pages.
|
|
SS$_LKWSETFUL
|
The locked working set is full. If any more pages are locked, not
enough dynamic pages will be available to continue execution.
|
|
SS$_NOPRIV
|
A page in the specified range is in the system address space, or a
global page with write access was specified.
|
|
SS$_PAGOWNVIO
|
The pages could not be locked because the access mode associated with
the call to $LKWSET was less privileged than the access mode associated
with the pages that were to be locked.
|
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