Document revision date: 15 July 2002

The Parse service analyzes the file specification string and fills in various NAM or NAML block fields.

Format

SYS$PARSE fab [,[err] [,suc]]

RETURNS

OpenVMS usage:	cond_value
type:	longword
access:	write only
mechanism:	by value

The value is returned in symbolic offset FAB$L_STS. Symbolic offset FAB$L_STV may contain additional status information.

Arguments

fab

OpenVMS usage:	fab
type:	longword (unsigned)
access:	modify
mechanism:	by reference

FAB control block whose contents are to be used as indirect arguments for the Parse service call. The fab argument is the address of the FAB control block.

err

OpenVMS usage:	ast_procedure
type:	procedure value
access:	call without stack unwinding
mechanism:	by reference

AST-level error completion routine that the service invokes if the operation is unsuccessful. The err argument is the address of the entry mask of this user-written completion routine.

suc

OpenVMS usage:	ast_procedure
type:	procedure value
access:	call without stack unwinding
mechanism:	by reference

AST-level success completion routine that the service invokes if the operation is successful. The suc argument is the address of the entry mask of this user-written completion routine.

Description

The functions of the Parse service are performed automatically as part of the Open, Create, and Erase services. One special purpose of the Parse service is to prepare the FAB and NAM or NAML blocks for wildcard character processing to be used in the Search service. If wildcard characters, search list logical names, or a node name are present in the file specification, RMS allocates internal data structures (including a device channel) to store the context for subsequent searches. This space is released when the Search service encounters a no-more-files condition (in which case an RMS$_NMF error status is returned) or when another Parse service is performed using the same FAB and NAM or NAML blocks. To release this space, use a Parse service that specifies the NAM$B_NOP field NAM$V_SYNCHK option and sets the FAB$B_DNS and NAM$L_RLF fields to zero. If you are using the NAML$L_LONG_DEFNAME and NAM$L_LONG_DEFNAME_SIZE fields, set the NAML$L_LONG_DEFNAME_SIZE field to zero in place of FAB$B_DNS.

Note that the file must be closed before you invoke the Parse service (FAB$W_IFI must be 0).

By default, the Parse service assigns a channel to the device and does a lookup of the directory in addition to analyzing the file specification and filling in the NAM or NAML block fields. To request a Parse service without I/O, specify the NAM$B_NOP field NAM$V_SYNCHK option. The result of a Parse service without I/O cannot be used as input to subsequent Search services.

The following tables list the fields in both the FAB and NAM or NAML blocks that the Parse service uses as input and output. In addition, RMS fills in the string component descriptors from the expanded string (see Chapter 5).

The expanded file specification string is moved to the buffer described by the expanded string area address (NAM$L_ESA) and size (NAM$B_ESS) fields of the NAM or NAML block (only if both fields are nonzero). The NAM$L_ESA and NAM$B_ESS fields must be specified (nonzero) for wildcard character processing.

Table RMS-55 lists the FAB control block fields read as input by the Parse service. For additional information on the fields accessed by this service, see Part 2.

Table RMS-55 Parse Service FAB Input Fields

Field Name	Option	Description
FAB$B_ACMODES		File access modes.
	FAB$V_CHAN_MODE 1	This field can be used to override the access mode protection for a specified I/O operation (see Section 4.8).
FAB$L_DNA		Default file specification string.
FAB$B_DNS		Default file specification string size.
FAB$L_FNA		File specification string address.
FAB$B_FNS		File specification string size.
FAB$L_FOP		File-processing option, FAB$V_OFP. Output file parse: indicates that RMS uses only the file name and file type fields of a related file resultant string whose address is contained in the NAM$L_RSA field.
FAB$W_IFI		Internal file identifier (must be zero).
FAB$L_NAM		NAM or NAML block address.

Table RMS-56 lists the FAB control block fields written as output by the Parse service.

Table RMS-56 Parse Service FAB Output Fields

Field Name	Description
FAB$L_DEV	Device characteristics (unless you select the NAM$V_SYNCHK option).
FAB$L_SDC	Secondary device characteristics (unless you select the NAM$V_SYNCHK option).
FAB$L_STS	Completion status code (also returned in register 0).
FAB$L_STV	Status value.

Table RMS-57 lists the NAM control block fields read as input by the Parse service. For additional information on the fields accessed by this service, see Part 2.

Table RMS-57 Parse Service NAM Input Fields

Field Name	Option	Description
NAM$L_ESA		Expanded string area address.
NAM$B_ESS		Expanded string area size.
NAM$L_FNB		Related file NAM block file name status bits.
NAM$B_NOP		NAM block options.
	NAM$V_NOCONCEAL	Do not conceal device name: indicates that when a concealed device logical name is present, the concealed device logical name is to be replaced by the actual physical device name in the expanded string.
	NAM$V_PWD	Password: indicates that a password contained in a DECnet for OpenVMS access control string, if present in a file specification, is to be left unaltered in the expanded and resultant strings (instead of being replaced by the word "password").
	NAM$V_NO_SHORT_UPCASE 1	Do not uppercase the directory and file specification in the NAM$L_ESA buffer.
	NAM$V_SYNCHK	Performs Parse service with no I/O.
NAM$L_RLF		Related file NAM or NAML block address.
NAM$L_RSA		Resultant string area address.
NAM$B_RSL		Resultant string length.

Table RMS-58 lists the NAM control block fields written as output by the Parse service.

Table RMS-58 Parse Service NAM Output Fields

Field Name	Description
NAM$L_DEV	Address of file specification device string.
NAM$B_DEV	Size of file specification device string.
NAM$W_DID 1	Directory identification (unless you select the NAM$V_SYNCHK option).
NAM$L_DIR	Address of file specification directory string.
NAM$B_DIR	Size of file specification directory string.
NAM$T_DVI 1	Device identification (unless you select the NAM$V_SYNCHK option).
NAM$B_ESL	Expanded string length.
NAM$W_FID 1	File identification (zeroed).
NAM$W_FIRST_WILD_DIR 1	The topmost directory level to contain a wildcard.
NAM$L_FNB	File name status bits: contains information about the parse results.
NAM$L_LONG_DIR_LEVELS 1	Total number of directories.
NAM$L_NAME	Address of file specification name string.
NAM$B_NAME	Size of file specification name string.
NAM$L_NODE	Address of file specification node string.
NAM$B_NODE	Size of file specification node string.
NAM$B_RSL	Resultant string length (zeroed).
NAM$L_TYPE	Address of file specification type string.
NAM$B_TYPE	Size of file specification type string.
NAM$L_VER	Address of file specification version string.
NAM$B_VER	Size of file specification version string.
NAM$L_WCC	Wildcard context.

Table RMS-59 lists the NAML block fields used as input for the Parse service.

Table RMS-59 Parse Service NAML Input Fields (Alpha Only)

Field Name	Option	Description
NAML$L_ESA		Expanded string area address.
NAML$B_ESS		Expanded string area size.
NAML$L_FILESYS_NAME 1		File system name buffer address.
NAML$L_FILESYS_NAME_ALLOC 1		File system name buffer size.
NAML$L_FNB		Related file NAM or NAML block file name status bits.
NAML$L_INPUT_FLAGS		Additional flags specified as input.
NAML$L_LONG_DEFNAME		Long default file specification string address (used if FAB$L_DNA contains -1).
NAML$L_LONG_DEFNAME_SIZE		Long default file specification string size.
NAML$L_LONG_EXPAND		Long expanded string area address.
NAML$L_LONG_EXPAND_ALLOC 1		Long expanded string area size.
NAML$L_LONG_FILENAME		Long file specification string address (used if FAB$L_FNA contains -1).
NAML$L_LONG_FILENAME_SIZE 1		Long file specification string size.
NAML$L_LONG_RESULT		Long resultant string area address.
NAML$L_LONG_RESULT_ALLOC		Long resultant string size.
NAML$B_NOP		NAM or NAML block options.
	NAML$V_NOCONCEAL	Do not conceal device name: indicates that when a concealed device logical name is present, the concealed device logical name is to be replaced by the actual physical device name in the expanded string.
	NAML$V_PWD	Password: indicates that a password contained in a DECnet for OpenVMS access control string, if present in a file specification, is to be left unaltered in the expanded and resultant strings (instead of being replaced by the word "password").
	NAML$V_NO_SHORT_UPCASE 1	Do not uppercase the directory and file specification in the NAML$L_ESA buffer.
	NAML$V_SYNCHK	Performs Parse service with no I/O.
NAML$L_RLF		Related file NAM or NAML block address.
NAML$L_RSA		Resultant string area address.
NAML$B_RSL		Resultant string length.

Table RMS-60 lists the NAML block fields used as output for the Parse service.

Table RMS-60 Parse Service NAML Output Fields (Alpha Only)

Field Name	Description
NAML$L_DEV	Address of file specification device string.
NAML$B_DEV	Size of file specification device string.
NAML$W_DID 1	Directory identification (unless you select the NAML$V_SYNCHK option).
NAML$L_DIR	Address of file specification directory string.
NAML$B_DIR	Size of file specification directory string.
NAML$T_DVI 1	Device identification (unless you select the NAML$V_SYNCHK option).
NAML$B_ESL	Expanded string length.
NAML$W_FID 1	File identification (zeroed).
NAML$L_FILESYS_NAME_SIZE 1	File system name length.
NAML$W_FIRST_WILD_DIR 1	First wild directory.
NAML$L_FNB	File name status bits: contains information about the parse results.
NAML$L_LONG_DEV	Long device string address.
NAML$L_LONG_DEV_SIZE	Long device string length.
NAML$L_LONG_DIR	Long directory string address.
NAML$W_LONG_DIR_LEVELS	Total number of directories.
NAML$L_LONG_DIR_SIZE	Long directory string length.
NAML$L_LONG_EXPAND_SIZE	Long expanded string length.
NAML$L_LONG_NAME	Long file name string address.
NAML$L_LONG_NAME_SIZE	Long file name string length.
NAML$L_LONG_NODE	Long node name string address.
NAML$L_LONG_NODE_SIZE	Long node name string length.
NAML$L_LONG_RESULT_SIZE	Long resultant string length.
NAML$L_LONG_TYPE	Long file type string length.
NAML$L_LONG_TYPE_SIZE	Long file type string address.
NAML$L_LONG_VER	Long file version string address.
NAML$L_LONG_VER_SIZE	Long file version string length.
NAML$L_NAME	Address of file specification name string.
NAML$B_NAME	Size of file specification name string.
NAML$L_NODE	Address of file specification node string.
NAML$B_NODE	Size of file specification node string.
NAML$L_OUTPUT_FLAGS	Additional status bits passed as output.
NAML$B_RSL	Resultant string length (zeroed).
NAML$L_TYPE	Address of file specification type string.
NAML$B_TYPE	Size of file specification type string.
NAML$L_VER	Address of file specification version string.
NAML$B_VER	Size of file specification version string.
NAML$L_WCC	Wildcard context.

Condition Values Returned

The following condition values can be returned. Use the Help Message utility to access online message descriptions. For more information about interpreting condition values, see Section 2.4.

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