Difference between revisions of "Category:Lexical Functions"
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m (Minor corrections: change "you must use the brackets" to "you must use the parentheses", and capitalize the "F" in "f$LICENSE" for consistency.) |
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F$function-name([args,...]) | F$function-name([args,...]) | ||
− | Note that you must use the | + | Note that you must use the parentheses even if no arguments are required. Sometimes it is required to specify an empty string ("") as an argument, and sometimes they follow a specific order and you need to keep the commas in place if you omit certain arguments. |
=Lexical functions by topic= | =Lexical functions by topic= | ||
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==Miscellaneous== | ==Miscellaneous== | ||
* [[F$MATCH_WILD()]] performs a wildcard matching between a candidate and a pattern string. | * [[F$MATCH_WILD()]] performs a wildcard matching between a candidate and a pattern string. | ||
− | * [[ | + | * [[F$LICENSE()]] checks whether the specified [[Licensing|license]] is loaded on the system. |
Latest revision as of 14:30, 16 April 2020
Lexical functions are constructs that return information about your OpenVMS system and arithmetic and string expressions and perform other functions. There are 43 lexical functions in OpenVMS 8.4-L2.
Contents
Format
F$function-name([args,...])
Note that you must use the parentheses even if no arguments are required. Sometimes it is required to specify an empty string ("") as an argument, and sometimes they follow a specific order and you need to keep the commas in place if you omit certain arguments.
Lexical functions by topic
Lexical functions serve a number of purposes: unit, data type, datetime conversion, returning information about system objects and establishing context for such information, etc.
Conversion and data types
- F$STRING() returns the string equivalent of the result of the specified expression.
$ write sys$output f$string(5) 5
- F$INTEGER() returns the integer equivalent of the result of the specified expression.
$ write sys$output f$integer("y") 1 $ write sys$output f$integer("a") 0
- F$IDENTIFIER() converts an identifier in named format to its integer equivalent, or vice versa.
$ WRITE SYS$OUTPUT F$IDENTIFIER("SLOANE","NAME_TO_NUMBER") 15728665
- F$CUNITS converts a number from one specified unit of measure to another.
- F$CVUI extracts bit fields from character string data and converts the result, as an unsigned value, to an integer.
- F$CVSI() extracts bit fields from character string data and converts the result, as a signed value, to an integer.
- F$TYPE determines the data type of a symbol
String operations
- F$LOCATE() locates a character or character substring within a string and returns its offset within the string.
$ WRITE SYS$OUTPUT F$LOCATE("E","HELLO") 1
- F$LENGTH() returns the length of a specified string.
$ WRITE SYS$OUTPUT F$LENGTH("HELLO") 5
- F$FAO() converts the specified control string to a formatted ASCII output string.
$ WRITE SYS$OUTPUT F$FAO("!5SL !5UB !5SL",-1,2,"pcs") -1 2 pcs $ REPORT = F$FAO("There !0UL!1%Cis!%Eare!%F !-!UL !-!0UL!1%Cchild!%Echildren!%F here",OFFSPRING) $ SHOW SYMBOL REPORT $ REPORT ="There is 1 child here"
- F$EXTRACT() extracts a substring from a character string expression.
$ WRITE SYS$OUTPUT F$EXTRACT("1",2,"HELLO") EL
- F$ELEMENT() extracts an element from a string in which the elements are separated by a specified delimiter.
$ WRITE SYS$OUTPUT F$ELEMENT(0,"/","1/2/3") 1
- F$EDIT() edits a character string based on the edits specified (upcases, removes spaces and comments).
$ WRITE SYS$OUTPUT F$EDIT(" HELLO ","COLLAPSE,LOWERCASE") hello
Files
- F$SEARCH() looks for the file you specify
- F$PARSE() invokes the $PARSE RMS service to parse a file specification and return either the expanded file specification or the particular file specification field that you request.
- F$FILE_ATTRIBUTES() returns attribute information for a specified file.
- F$FID_TO_NAME() translates a file identification to a file specification.
Processes
- F$CONTEXT specifies selection criteria for use with the F$PID function.
- F$GETJPI returns accounting, status, and identification information for a process.
- F$PID() for each invocation, returns the next process identification number in sequence.
Devices
- F$DEVICE() returns device names of all devices on a system that meet the specified selection criteria.
- F$GETDVI() returns information about a specified device.
- F$MULTIPATH() returns a specified item of information for a specific multipath-capable device.
Time
- F$TIME() returns the current date and time of day, in the format dd-mmm-yyyy hh:mm:ss.cc.
- F$DELTA_TIME() returns the time difference between a given start and end time.
- F$CVTIME() retrieves information about an absolute, combination, or delta time string.
System and cluster
- F$GETSYI() returns 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$CSID() returns an OpenVMS Cluster identification number and updates the context symbol to point to the current position in the system's cluster node list.
Queues
- F$GETQUI() returns information about queues, batch and print jobs currently in those queues, form definitions, and characteristic definitions kept in the queue database.
Logical names
F$TRNLNM() used for translating logical names and obtaining their attributes.
User environment
- F$USER() returns the current user's 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.
- F$PROCESS() returns the current process name string.
- F$MODE() shows the mode in which a process is executing.
- F$MESSAGE() returns the message text associated with a specified system status code value.
- F$GETENV() returns the value of the specified console environment variable.
- F$ENVIRONMENT() obtains information about the DCL command environment.
- F$DIRECTORY() returns the current default directory name string.
Privileges
- F$SETPRV() sets the specified privileges and returns a list of keywords indicating the previous state of these privileges for the current process.
- F$PRIVILEGE() returns a value of TRUE or FALSE depending on whether your current process privileges match the privileges listed in the argument.
Miscellaneous
- F$MATCH_WILD() performs a wildcard matching between a candidate and a pattern string.
- F$LICENSE() checks whether the specified license is loaded on the system.
Pages in category "Lexical Functions"
The following 41 pages are in this category, out of 41 total.
F
- F$CONTEXT
- F$CSID()
- F$CUNITS
- F$CVSI()
- F$CVTIME()
- F$CVUI
- F$DELTA TIME()
- F$DEVICE()
- F$DIRECTORY()
- F$EDIT()
- F$ELEMENT()
- F$ENVIRONMENT()
- F$EXTRACT()
- F$FAO()
- F$FILE ATTRIBUTES()
- F$GETDVI()
- F$GETENV()
- F$GETJPI
- F$GETQUI Context
- F$GETQUI()
- F$GETSYI()
- F$IDENTIFIER()
- F$INTEGER()
- F$LENGTH()
- F$LICENSE()
- F$LOCATE()
- F$MATCH WILD()
- F$MESSAGE()
- F$MODE()
- F$MULTIPATH()
- F$PARSE()
- F$PID()
- F$PRIVILEGE()
- F$PROCESS()
- F$SEARCH()
- F$SETPRV()
- F$STRING()
- F$TIME()
- F$TRNLNM()
- F$TYPE
- F$VERIFY()