OpenVMS System Services Reference Manual

Document revision date: 30 March 2001

OpenVMS System Services Reference Manual

Contents

Index

$GET_ARITH_EXCEPTION (Alpha Only)

On Alpha systems, returns information about the exception context for a given arithmetic exception.

Format

SYS$GET_ARITH_EXCEPTION sigarg ,mcharg ,buffer

C Prototype

int sys$get_arith_exception (void *sigarg, void *mcharg, void *buffer);

Arguments

sigarg

OpenVMS usage: signal array

type: vector_longword_signed

access: read only

mechanism: by reference

Address of the signal array for the given arithmetic exception.
mcharg

OpenVMS usage: mech array

type: vector_quadword_unsigned

access: read only

mechanism: by reference

Address of the mechanism array for the given arithmetic exception.
buffer

OpenVMS usage: vector_quadword

type: vector_quadword_unsigned

access: write only

mechanism: by descriptor

Four-quadword buffer to receive additional exception context. The buffer argument is the address of a descriptor that points to this buffer.

Description

The Get Arithmetic Exception Information service returns, to the buffer specified by the buffer argument, the following information for a given arithmetic exception in an array of quadwords:

First quadword, the PC of the triggering instruction in the trap shadow
Second quadword, a copy of the triggering instruction
Third quadword, the exception summary
Fourth quadword, the register write mask

Required Access or Privilege

None
Required Quota

None

Condition Values Returned

SS$_NORMAL The service completed successfully.

SS$_ACCVIO The specified buffer cannot be written.

SS$_BADBUFLEN The specified buffer length is invalid or out of range.

$GET_GALAXY_LOCK_INFO (Alpha Only)

Returns "interesting" fields from the specified lock.
Note that this system service is supported only in an OpenVMS Alpha Galaxy environment. For more information about programming with OpenVMS Galaxy system services, refer to the OpenVMS Alpha Partitioning and Galaxy Guide.

Format

SYS$GET_GALAXY_LOCK_INFO handle ,name ,timeout ,size ,ipl ,rank ,flags [,name_length]

C Prototype

int sys$get_galaxy_lock_info (unsigned __int64 lock_handle, char *name, unsigned int *timeout, unsigned int *size, unsigned int *ipl, unsigned int *rank, unsigned short int *flags unsigned short int *name_length);

Arguments

handle

OpenVMS usage: handle for the galaxy lock

type: quadword (unsigned)

access: read

mechanism: input by value

The 64-bit lock handle that identifies the lock on which to return information. This value is returned by SYS$CREATE_GALAXY_LOCK.
name

OpenVMS usage: address

type: zero-terminated string

access: write

mechanism: output by reference

Pointer to a buffer. This buffer must be large enough to receive the name of the lock. Locks names are zero-terminated strings with a maximum size of 16 bytes.
timeout

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is the timeout value of the lock.
size

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is the size of the lock in bytes.
ipl

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is the IPL of the lock.
rank

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is the rank of the lock.
flags

OpenVMS usage: address

type: word (unsigned)

access: write

mechanism: output by reference

Pointer to a word. The value returned is the word mask of lock flags.
name_length

OpenVMS usage: address

type: word (unsigned)

access: write

mechanism: output by reference

Length of the string returned in the name argument.

Description

This service returns all "interesting" fields from the specified lock. See the $CREATE_GALAXY_LOCK service for detailed information regarding these values.
Required Access or Privileges

Read access to lock.
Required Quota

None
Related Services

$ACQUIRE_GALAXY_LOCK, $CREATE_GALAXY_LOCK, $CREATE_GALAXY_LOCK_TABLE, $DELETE_GALAXY_LOCK, $DELETE_GALAXY_LOCK_TABLE, $GET_GALAXY_LOCK_SIZE, $RELEASE_GALAXY_LOCK

Condition Values Returned

SS$_NORMAL Normal completion.

SS$_IVLOCKID Invalid lock id.

SS$_IVLOCKTBL Invalid lock table.

$GET_GALAXY_LOCK_SIZE (Alpha Only)

Returns the minimum and maximum size of an OpenVMS Galaxy lock.
Note that this system service is supported only in an OpenVMS Alpha Galaxy environment.
For more information about programming with OpenVMS Galaxy system services, refer to the OpenVMS Alpha Partitioning and Galaxy Guide.

Format

SYS$GET_GALAXY_LOCK_SIZE min_size ,max_size

C Prototype

int sys$get_galaxy_lock_size (unsigned int *min_size, unsigned int *max_size);

Arguments

min_size

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is minimum legal size of a galaxy lock structure.
max_size

OpenVMS usage: address

type: longword (unsigned)

access: write

mechanism: output by reference

Pointer to a longword. The value returned is maximum legal size of a galaxy lock structure.

Description

This service returns the minimum and maximum size of an OpenVMS Galaxy lock. If a lock is created with the maximum size, the locking services will record acquire and release information in the lock.
The lock sizes can be used to determine the value of the section_size parameter to the $CREATE_GALAXY_LOCK_TABLE service.
Required Access or Privileges

Read access to lock.
Required Quota

None
Related Services

$ACQUIRE_GALAXY_LOCK, $CREATE_GALAXY_LOCK, $CREATE_GALAXY_LOCK_TABLE, $DELETE_GALAXY_LOCK, $DELETE_GALAXY_LOCK_TABLE, $GET_GALAXY_LOCK_INFO, $RELEASE_GALAXY_LOCK

Condition Values Returned

SS$_NORMAL Normal completion.

$GET_REGION_INFO (Alpha Only)

On Alpha systems, gets information about a specified virtual region.
This service accepts 64-bit addresses.

Format

SYS$GET_REGION_INFO function_code ,region_id_64 ,start_va_64 ,nullarg ,buffer_length ,buffer_address_64 ,return_length_64

C Prototype

int sys$get_region_info (unsigned int function_code, struct _generic_64 *region_id_64, void *start_va_64, void *reserved, unsigned int buffer_length, void *buffer_address_64, unsigned int *return_length_64);

Arguments

function_code

OpenVMS usage: function code

type: longword (unsigned)

access: read only

mechanism: by value

Function code specifying how the information you are requesting should be looked up. All function codes return region summary information in the return buffer in the format of the Region Summary Buffer. The Region Summary Buffer format is shown in the table in the buffer_address_64 argument.
If less buffer space is specified than the length of the Region Summary Buffer, only the amount of information requested is returned. If more buffer space is specified than the length of the Region Summary Buffer, the service will fill in the buffer. The return length will reflect the amount of useful information written to the buffer, the size of the Region Summary Buffer.
The file VADEF.H in SYS$STARLET_C.TLB and the $VADEF macro in STARLET.MLB define a symbolic name for each function code.
The following function codes are defined:

Symbolic Name Description

VA$_REGSUM_BY_ID Return the region summary information for the region whose ID is specified in the region_id_64 argument.

VA$_REGSUM_BY_VA Return the region summary information for the region that contains the virtual address specified in the start_va_64 argument.

VA$_NEXT_REGSUM_BY_VA Return the region summary information for the region containing the starting address. If the starting address is not in a region, return the region summary information for the next region with a starting address higher than the specified address.
Note: For the VA$_NEXT_REGSUM_BY_VA function, OpenVMS checks for a start_va_64 argument in the inaccessible address range in P2 space. If it finds one, OpenVMS adjusts the address to account for the discontinuity. For more information about the layout of the 64-bit virtual address space, refer to the OpenVMS Programming Concepts Manual.
This function code can be used for wildcard operations. See the description of the start_va_64 argument for information on how to program a wildcard operation on regions.

region_id_64

OpenVMS usage: region identifier

type: quadword (unsigned)

access: read only

mechanism: by 32- or 64-bit reference

The region ID associated with the region about which information is requested. This argument is read only if the function code VA$_REGSUM_BY_ID is specified.
The file VADEF.H in SYS$STARLET_C.TLB and the $VADEF macro in STARLET.MLB define a symbolic name for each of the three default regions in P0, P1, and P2 space.
The following region IDs are defined:

Symbol Region

VA$C_P0 Program region

VA$C_P1 Control region

VA$C_P2 64-bit program region

Other region IDs, as returned by the $CREATE_REGION_64 service, can be specified.
start_va_64

OpenVMS usage: input address

type: quadword address

access: read only

mechanism: by value

Virtual address associated with region about which information is requested. This argument is read only if the function_code argument is VA$_REGSUM_BY_VA or VA$_NEXT_REGSUM_BY_VA.
If the function_code argument is VA$_REGSUM_BY_VA, this argument is a virtual address within the region about which you are requesting information.
To perform a wildcard search on all regions, specify VA$_NEXT_REGSUM_BY_VA as the function code and begin with the start_va_64 argument specified as -1. For subsequent calls, specify start_va_64 as the sum of the previous region's start address and length. Call the $GET_REGION_INFO service in a loop until the condition SS$_NOMOREREG is returned.

Note
Before performing the lookup function, OpenVMS sign-extends the 64-bit starting address so that it represents a properly formed virtual address for the CPU.

nullarg

OpenVMS usage: null_arg

type: longword (unsigned)

access: read only

mechanism: by value

Placeholding argument reserved to Compaq.
buffer_length

OpenVMS usage: longword_unsigned

type: longword (unsigned)

access: read only

mechanism: by value

Length of the buffer into which information is returned.
buffer_address_64

OpenVMS usage: varying_arg

type: unspecified

access: write only

mechanism: by 32- or 64-bit reference

The 32- or 64-bit virtual address of a quadword-aligned buffer into which to return information if the buffer_length argument is nonzero.
This argument is ignored if the buffer_length argument is zero.
Table SYS-14 shows the format of the Region Summary Buffer:

Table SYS-14 Region Summary Buffer Format
Field name Meaning Field Size (Bytes) Field Offset (Decimal)

VA$L_FLAGS Flags used when region was created 4 8

VA$L_REGION_PROTECT Create and owner mode of region 4 12

VA$Q_REGION_ID Region identifier 8 0

VA$PQ_START_VA Starting (lowest) virtual address of region 8 16

VA$Q_REGION_SIZE Total length of region 8 24

VA$PQ_FIRST_FREE_VA First free virtual address in region 8 32

VA$C_REGSUM_LENGTH Length of Region Summary Buffer constant 40

The file VADEF.H in SYS$STARLET_C.TLB and the $VADEF MACRO in STARLET.MLB define the REGSUM structure.
return_length_64

OpenVMS usage: longword_unsigned

type: longword (unsigned)

access: write only

mechanism: by 32- or 64-bit reference

The 32- or 64-bit virtual address of a naturally aligned longword into which the service returns the length of the information in bytes.

Symbolic Name	Description
VA$_REGSUM_BY_ID	Return the region summary information for the region whose ID is specified in the region_id_64 argument.
VA$_REGSUM_BY_VA	Return the region summary information for the region that contains the virtual address specified in the start_va_64 argument.
VA$_NEXT_REGSUM_BY_VA	Return the region summary information for the region containing the starting address. If the starting address is not in a region, return the region summary information for the next region with a starting address higher than the specified address. Note: For the VA$_NEXT_REGSUM_BY_VA function, OpenVMS checks for a start_va_64 argument in the inaccessible address range in P2 space. If it finds one, OpenVMS adjusts the address to account for the discontinuity. For more information about the layout of the 64-bit virtual address space, refer to the OpenVMS Programming Concepts Manual. This function code can be used for wildcard operations. See the description of the start_va_64 argument for information on how to program a wildcard operation on regions.

Symbol	Region
VA$C_P0	Program region
VA$C_P1	Control region
VA$C_P2	64-bit program region

**Table SYS-14 Region Summary Buffer Format**
Field name	Meaning	Field Size (Bytes)	Field Offset (Decimal)
VA$L_FLAGS	Flags used when region was created	4	8
VA$L_REGION_PROTECT	Create and owner mode of region	4	12
VA$Q_REGION_ID	Region identifier	8	0
VA$PQ_START_VA	Starting (lowest) virtual address of region	8	16
VA$Q_REGION_SIZE	Total length of region	8	24
VA$PQ_FIRST_FREE_VA	First free virtual address in region	8	32
VA$C_REGSUM_LENGTH	Length of Region Summary Buffer	constant	40

Description

The Get Information About a Specified Virtual Region service is a kernel mode service that can be called from any mode. This service gets the requested information about the specified region or the next region in a wildcard search. If the returned value of this service is not a successful condition value, a value cannot be returned in the memory locations pointed to by the buffer_address_64 or return_length_64 arguments.
Required Privileges

None
Required Quota

None
Related Services

$CREATE_REGION_64, $DELETE_REGION_64

Condition Values Returned

SS$_NORMAL The service completed successfully.

SS$_ACCVIO The buffer_address_64 argument or the return_length_64 argument cannot be written by the caller.

SS$_BADPARAM Unrecognized function code.

SS$_IVREGID Invalid region ID specified in conjunction with the VA$_REGSUM_BY_ID function code.

SS$_NOMOREREG No region at a higher address than specified in the start_va_64 argument, which was specified in conjunction with the wildcard function code VA$_NEXT_REGSUM_BY_VA.

SS$_PAGNOTINREG The value specified in the start_va_64 argument is not within a region and was specified in conjunction with the function code VA$_REGSUM_BY_VA.

$GET_SECURITY

Retrieves the security characteristics of an object.

Format

SYS$GET_SECURITY [clsnam] ,[objnam] ,[objhan] ,[flags] ,[itmlst] ,[contxt] ,[acmode]

C Prototype

int sys$get_security ( void *clsnam, void *objnam, unsigned int *objhan, unsigned int flags, void *itmlst, unsigned int *contxt, unsigned int *acmode);

Arguments

clsnam

OpenVMS usage: char_string

type: character-coded text string

access: read only

mechanism: by descriptor

Name of the object class. The clsnam argument is the address of a descriptor pointing to a string containing the name of the object class.
The following is a list of protected object class names:
CAPABILITY
COMMON_EVENT_CLUSTER
DEVICE
FILE
GLXSYS_GLOBAL_SECTION
GLXGRP_GLOBAL_SECTION
GROUP_GLOBAL_SECTION
ICC_ASSOCIATION
LOGICAL_NAME_TABLE
QUEUE
RESOURCE_DOMAIN
SECURITY_CLASS
SYSTEM_GLOBAL_SECTION
VOLUME

objnam

OpenVMS usage: char_string

type: character-coded text string

access: read only

mechanism: by descriptor

Name of the protected object whose associated security profile is going to be retrieved. The objnam argument is the address of a descriptor pointing to a string containing the name of the protected object.
The format of an object name is class specific. The following table lists object names and describes their formats:

Object Class Object Name Format

CAPABILITY A character string. Currently, the only capability object is VECTOR.

COMMON_EVENT_CLUSTER Name of the event flag cluster, as defined in the Associate Common Event Flag Cluster ($ASCEFC) system service.

DEVICE Standard device specification, described in the OpenVMS User's Manual.

FILE Standard file specification, described in the OpenVMS User's Manual.

GROUP_GLOBAL_SECTION Section name, as defined in the Create and Map Section ($CRMPSC) system service.

ICC_ASSOCIATION ICC security object name node::association_name. The special node name, ICC$::, refers to entries in the clusterwide registry. For registry entries, the Access Access Type does not apply.

LOGICAL_NAME_TABLE Table name, as defined in the Create Logical Name Table ($CRELNT) system service.

QUEUE Standard queue name, as described in the Send to Job Controller ($SNDJBC) system service.

RESOURCE_DOMAIN An identifier or octal string enclosed in brackets.

SECURITY_CLASS Any class name shown in column 1, or a class name followed by a period (.) and the template name. Use the DCL command SHOW SECURITY to display possible template names.

SYSTEM_GLOBAL_SECTION Section name, as defined in the Create and Map Section ($CRMPSC) system service.

VOLUME Volume name or name of the device on which the volume is mounted.

objhan

OpenVMS usage: object_handle

type: longword (unsigned)

access: read only

mechanism: by reference

Data structure identifying the object whose associated characteristics are going to be retrieved. The objhan argument is an address of a longword containing the object handle. You can use the objhan argument as an alternative to the objnam argument; for example, channel number clearly specifies the file open on the channel and can serve as an object handle.
The following table shows the format of the object classes:

Object Class Object Handle Format

COMMON_EVENT_CLUSTER Event flag number

DEVICE Channel number

FILE Channel number

RESOURCE_DOMAIN Resource domain identifier

VOLUME Channel number

flags

OpenVMS usage: flags

type: mask_longword

access: read only

mechanism: by value

Mask specifying processing options. The flags argument is a longword bit vector wherein a bit, when set, specifies the processing option. The flags argument requires the contxt argument.

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OpenVMS usage:	signal array
type:	vector_longword_signed
access:	read only
mechanism:	by reference

OpenVMS usage:	mech array
type:	vector_quadword_unsigned
access:	read only
mechanism:	by reference

OpenVMS usage:	vector_quadword
type:	vector_quadword_unsigned
access:	write only
mechanism:	by descriptor

SS$_NORMAL	The service completed successfully.
SS$_ACCVIO	The specified buffer cannot be written.
SS$_BADBUFLEN	The specified buffer length is invalid or out of range.

OpenVMS usage:	handle for the galaxy lock
type:	quadword (unsigned)
access:	read
mechanism:	input by value

OpenVMS usage:	address
type:	zero-terminated string
access:	write
mechanism:	output by reference

SS$_NORMAL	Normal completion.
SS$_IVLOCKID	Invalid lock id.
SS$_IVLOCKTBL	Invalid lock table.

OpenVMS usage:	function code
type:	longword (unsigned)
access:	read only
mechanism:	by value

OpenVMS usage:	region identifier
type:	quadword (unsigned)
access:	read only
mechanism:	by 32- or 64-bit reference

OpenVMS usage:	input address
type:	quadword address
access:	read only
mechanism:	by value

OpenVMS usage:	null_arg
type:	longword (unsigned)
access:	read only
mechanism:	by value

OpenVMS usage:	longword_unsigned
type:	longword (unsigned)
access:	read only
mechanism:	by value

OpenVMS usage:	varying_arg
type:	unspecified
access:	write only
mechanism:	by 32- or 64-bit reference

OpenVMS usage:	char_string
type:	character-coded text string
access:	read only
mechanism:	by descriptor

Object Class	Object Name Format
CAPABILITY	A character string. Currently, the only capability object is VECTOR.
COMMON_EVENT_CLUSTER	Name of the event flag cluster, as defined in the Associate Common Event Flag Cluster ($ASCEFC) system service.
DEVICE	Standard device specification, described in the OpenVMS User's Manual.
FILE	Standard file specification, described in the OpenVMS User's Manual.
GROUP_GLOBAL_SECTION	Section name, as defined in the Create and Map Section ($CRMPSC) system service.
ICC_ASSOCIATION	ICC security object name node::association_name. The special node name, ICC$::, refers to entries in the clusterwide registry. For registry entries, the Access Access Type does not apply.
LOGICAL_NAME_TABLE	Table name, as defined in the Create Logical Name Table ($CRELNT) system service.
QUEUE	Standard queue name, as described in the Send to Job Controller ($SNDJBC) system service.
RESOURCE_DOMAIN	An identifier or octal string enclosed in brackets.
SECURITY_CLASS	Any class name shown in column 1, or a class name followed by a period (.) and the template name. Use the DCL command SHOW SECURITY to display possible template names.
SYSTEM_GLOBAL_SECTION	Section name, as defined in the Create and Map Section ($CRMPSC) system service.
VOLUME	Volume name or name of the device on which the volume is mounted.

OpenVMS usage:	object_handle
type:	longword (unsigned)
access:	read only
mechanism:	by reference

Object Class	Object Handle Format
COMMON_EVENT_CLUSTER	Event flag number
DEVICE	Channel number
FILE	Channel number
RESOURCE_DOMAIN	Resource domain identifier
VOLUME	Channel number

OpenVMS usage:	flags
type:	mask_longword
access:	read only
mechanism:	by value