HP OpenVMS Systems Documentation

A set of functions that return information about character strings and attributes of the current process.

Description

The command language includes constructs, called lexical functions, that return information about the current process and about arithmetic and string expressions. The functions are called lexical functions because the command interpreter evaluates them during the command input scanning (or lexical processing) phase of command processing.

You can use lexical functions in any context in which you normally use symbols or expressions. In command procedures, you can use lexical functions to translate logical names, to perform character string manipulations, and to determine the current processing mode of the procedure.

The general format of a lexical function is as follows:

F$function-name([args,...])

where:

F$	Indicates that what follows is a lexical function.
function-name	A keyword specifying the function to be evaluated. Function names can be truncated to any unique abbreviation.
()	Enclose function arguments, if any. The parentheses are required for all functions, including functions that do not accept any arguments.
args,...	Specify arguments for the function, if any, using integer or character string expressions.

For more information on specifying expressions, see the OpenVMS User's Manual.

Table DCLI-3 lists each lexical function and briefly describes the information that each function returns. A detailed description of each function, including examples, is given in the following pages.

Table DCLI-3 Summary of Lexical Functions

Function	Description
F$CONTEXT	Specifies selection criteria for use with the F$PID function.
F$CSID	Returns an OpenVMS Cluster identification number and updates the context symbol to point to the current position in the system's cluster node list.
F$CUNITS	Converts a number from one specified unit of measure to another.
F$CVSI	Extracts bit fields from character string data and converts the result, as a signed value, to an integer.
F$CVTIME	Retrieves information about an absolute, combination, or delta time string.
F$CVUI	Extracts bit fields from character string data and converts the result, as an unsigned value, to an integer.
F$DELTA_TIME	Returns the time difference between a given start and end time.
F$DEVICE	Returns device names of all devices on a system that meet the specified selection criteria.
F$DIRECTORY	Returns the current default directory name string.
F$EDIT	Edits a character string based on the edits specified.
F$ELEMENT	Extracts an element from a string in which the elements are separated by a specified delimiter.
F$ENVIRONMENT	Obtains information about the DCL command environment.
F$EXTRACT	Extracts a substring from a character string expression.
F$FAO	Invokes the $FAO system service to convert the specified control string to a formatted ASCII output string.
F$FID_TO_NAME (Alpha/Integrity servers only)	Translates a file identification to a file specification.
F$FILE_ATTRIBUTES	Returns attribute information for a specified file.
F$GETDVI	Invokes the $GETDVI system service to return a specified item of information for a specified device.
F$GETENV (Alpha only)	Invokes the $GETENV system service to return the value of the specified console environment variable.
F$GETJPI	Invokes the $GETJPI system service to return accounting, status, and identification information for a process.
F$GETQUI	Invokes the $GETQUI system service to return information about queues, batch and print jobs currently in those queues, form definitions, and characteristic definitions kept in the queue database.
F$GETSYI	Invokes the $GETSYI system service to return status and identification information about the local system, or about a node in the local cluster, if your system is part of a cluster.
F$IDENTIFIER	Converts an identifier in named format to its integer equivalent, or vice versa.
F$INTEGER	Returns the integer equivalent of the result of the specified expression.
F$LENGTH	Returns the length of a specified string.
F$LICENSE (Alpha/Integrity servers only)	Checks whether the specified license is loaded on the system.
F$LOCATE	Locates a character or character substring within a string and returns its offset within the string.
F$MATCH_WILD	Performs a wildcard matching between a candidate and a pattern string.
F$MESSAGE	Returns the message text associated with a specified system status code value.
F$MODE	Shows the mode in which a process is executing.
F$MULTIPATH (Alpha/Integrity servers only)	Returns a specified item of information for a specific multipath-capable device.
F$PARSE	Invokes the $PARSE RMS service to parse a file specification and return either the expanded file specification or the particular file specification field that you request.
F$PID	For each invocation, returns the next process identification number in sequence.
F$PRIVILEGE	Returns a value of TRUE or FALSE depending on whether your current process privileges match the privileges listed in the argument.
F$PROCESS	Returns the current process name string.
F$SEARCH	Invokes the $SEARCH RMS service to search a directory file, and returns the full file specification for a file you name.
F$SETPRV	Sets the specified privileges and returns a list of keywords indicating the previous state of these privileges for the current process.
F$STRING	Returns the string equivalent of the result of the specified expression.
F$TIME	Returns the current date and time of day, in the format dd-mmm-yyyy hh:mm:ss.cc.
F$TRNLNM	Translates a logical name and returns the equivalence name string or the requested attributes of the logical name.
F$TYPE	Determines the data type of a symbol.
F$UNIQUE (Alpha/Integrity servers only)	Generates a string that is suitable to be a file name and is guaranteed to be unique across the cluster.
F$USER	Returns the current user identification code (UIC).
F$VERIFY	Returns the integer 1 if command procedure verification is set on; returns the integer 0 if command procedure verification is set off. The F$VERIFY function also can set new verification states.