List of all Arity/Prolog32 predicates

;

Specifies a disjunction of goals.

!

The cut goal; controls and limits searches.

[! !]

Snips; the goal or goals within the snip symbols are skipped during backtracking.

E1 < E2

Determines whether the value of E1 is less than E2.

T1 = T2

Attempts to unify T1 and T2.

T1 \= T2

Fails if T1 unifies with T2.

Struct =.. List

Referred to as univ. Converts a structure to a list, or a list to a structure.

E1 =< E2

Determines whether the value of E1 is less than or equal to the value of E2.

E1 > E2

Determines whether the value of E1 is greater than the value of E2.

E1 >= E2

Determines whether the value of E1 is greater than or equal to the value of E2.

E1 =:= E2

Determines whether the values of E1 and E2 are equal.

E1 =\= E2

Determines whether the values of E1 and E2 are not equal.

T1 == T2

Determines whether terms T1 and T2 are equivalent.

+ P

Succeeds if the goal P fails; fails if P succeeds. Same as not(P).

T1 \== T2

Determines whether terms T1 and T2 are not equivalent.

T1 @< T2

Determines whether T1 is before T2.

T1 @=< T2

Determines whether T1 is before or equal to T2.

T1 @> T2

Determines whether T1 is after T2.

T1 @>= T2

Determines whether T1 is after or equal to T2.

[Filename,Filename,...]

Reads clauses into the database from a file with the consult predicate. -Filename uses the reconsult predicate.

abolish(+Name/Arity)

Removes all clauses with the specified name and arity from the database.

abort(+Code)

Goes to restart predicate. If there is no restart predicate, a compiled program halts and interpreted program returns to the interpreter.

arg(+N,+Term,-Value)

Unifies Value with the Nth argument of a term.

arg0(+N,+Term,-Value)

Unifies Value with the N+1th argument of a term.

argrep(+Term,+N,+Arg,-Newterm)

Replaces the Nth argument in a term with Arg and returns the result to Newterm.

assert(+Clause)

Adds a clause to a predicate. Equivalent to assertz.

assert(+Clasue,+N)

Adds a clause to a predicate as the Nth clause.

asserta(+Clause)

Adds a clause to the beginning of a chain of clauses for a predicate.

assertz(+Clause)

Adds a clause to the end of a chain of clauses for a predicate.

atom(?X)

Succeeds when X is an atom.

atom_string(?Atom,?String)

Deprecated. Atoms and strings are the same data type, so there is no need for conversion.

atomic(?X)

Succeeds if X is an atomic data type.

bagof(?Term,+Goal,-Bag)

Returns in an unordered list (Bag) all instances of Term where Goal is satisfied.

begin_choices(+Key)

The begin_choices/1 predicate has effect in one specific context: During the process of consulting code, any terms that appear between begin_choices/1 and its matching end_choices/1 are loaded into the database under Key.

betweenb(+BTree,?Key1,?Key2,?Relation1,?Relation2,?Key,?Term)

Returns the terms in a B-tree between Key1 and Key2. The Relation1 and Relation2 arguments indicate whether the limit keys are returned and can be <, >, or =.

betweenkeysb(+BTree,?Key1,?Key2,?Key)

Returns only the keys between Key1 and Key2 in a B-tree.

bit_count(+Int,-Count)

Returns a count of the number of bits in an integer that have a value of 1.

bit_lit(+Bit,+Int)

Succeeds if a specified bit has the value of 1 within theinteger.

bit_unlit(+Bit,+Int)

Succeeds if a specified bit has the value of 0 within the integer.

break

Suspends execution of a program and places you at the interpreter prompt. You can resume the program by pressing Ctrl-z.

btree_count(+Btree,-/+Count)

Returns the number of keys in the btree.

call(+P)

Calls the interpreted goal P and succeeds if P succeeds.

call(+A,+P)

Calls the interpreted goal P and succeeds if P succeeds using the address structure generated by evalAddress/2.

case(+[A1 -> B1, A2 -> B2,...|C])

Executes B1 if A1 succeeds, else executes B2 if A2 succeeds, and so on. If none of the situations succeed, C is executed.

case(+[A1 -> B1, A2 -> B2,...])

Executes B1 if A1 succeeds, else executes B2 if A2 succeeds, and so on. If none of the situations succeed, case succeeds.

chdir(?Path)

Changes or returns the current directory.

chmod(+Filename,?Attributes)

Changes or returns the attribute byte of a file.

Unifies Head and Body with the respective head and body of a clause. Head must be instantiated.

close(+Handle)

Closes the file specified by the handle.

cls

Clears the current window and moves the cursor to the upper left corner.

code_world(?Old,?New)

Unifies the name of the current code world with Old and then changes the current code world to New.

command_string(-X)

Returns a command line argument as a string, including any spaces between the command and the first argument. The format of this string is system dependent.

compare(-Comp,+T1,+T2)

compare(-Comp,+T1,+T2,+Case)

Compares terms T1 and T2 in the standard order and unifies Comp with a comparison value. Comparison values are: =, <, and >. The Case argument can be used to specify the case sensitivity of the comparison: 0 - sensitive; 1 - insensitive.

concat(+String1,+String2,-Result)

Concatenates two strings or atoms and returns the new string to Result. An ASCII code can be used for a string if it is asingle character.

concat(+[String1,String2,...], -Result)

Concatenates two or more strings or atoms and returns the new string to Result. An ASCII code can be used for a string if it is a single character.

consult(+Filename)

Reads clauses into the database from a file, appending the clauses to any already in the database.

create(-Handle,+Filename)

Creates and opens a new file for writing and returns the file's handle. If Filename already exists, the new file overwrites the existing file.

create_world(+WorldName)

Creates a new world with the world name specified.

ctr_dec(+Ctr,-X)

Decrements a counter and returns the counter's previous value.

ctr_inc(+Ctr,-X)

Increments a counter and returns the counter's previous value.

ctr_is(+Ctr,-X)

Returns the current value of a counter.

ctr_set(+Ctr,+X)

Sets a counter to the specified value.

current_op(?Prec,?Assoc,?Op)

Returns through backtracking the operator definitions currently in the database.

current_predicate(?Predicate)

Returns through backtracking the predicates that are in the current code world. If instantiated, the Predicate argument can be a predicate name or name/arity.

data_world(?Old,?New)

Unifies the name of the current data world with Old and then changes the current data world to New.

date(?date(Year,Month,Day))

Sets the system clock to the date specified or returns the current date.

date_day(+date(Year,Month,Day),-WeekDay)

Returns the day of the week for a given date as an integer between 0 (Sunday) and 6 (Saturday).

dbcs2term(+Ptr,-Term)

Decodes the C string at Ptr as Term.

dbPartition(-OldPartition,+NewPartition)

Gets / sets the default database partition.

dbs2term(+DBString,-Term)

Decodes the Prolog string DBString as Term.

dbsLen(+Term,-Len)

Returns the byte length of the string that would be created using term2dbs/2 or term2dbcs/4.

debug

debug(+File)

Turns the debugger on, initialy set to leap mode. If File is specified, then it is created and debugger output is echoed into the File.

debugger

Provides debug statistics on current debug mode and spied predicates.

dec(+N,-X)

Decrements by 1 the integer N to the value X.

defineb(+BTree,+SplitSize,+Uniqueness,+Order)

defineb(+BTree,+SplitSize,+Uniqueness,+Order,+Case)

Defines the attributes for a B-tree.

defineh(+Table_Name,+HashBuckets)

Defines the number of hash buckets to be used in a hash table.

delete(+Filename)

Deletes the specified file.

deleteworld(+Worldname)

Deletes a world.

directory(+Path,-Name,-Mode,-Time,-Date,-Size)

Lists the directory files specified by Path. The Mode can be:

1 - read only;

2 - hidden;

4 - system file excluded from normal directory searches;

16 - directory;

32 - archive.

disk(?DiskName)

Sets or returns the default disk drive to the letter specified. If instantiated, do not specify the colon with DiskName.

display(+Term)

display(+Handle,+Term)

Writes a term in prefix Polish form to the standard output device or the specified file Handle.

This predicate looks up addresses of exported items in a DLL. You can specify the DLL by name or handle. Item is either:

• An integer: look up the address by ordinal.
• A predicate specification Func/Arity: look up the name corresponding to the Prolog predicate.
• An atom: look up the entrypoint by name.

dll_free(+NameOrHandle)

Frees a DLL that was loaded using dll_load/3. The name must exactly match the name used when the DLL was loaded. If NameOrHandle is an integer, then this predicate unloads the DLL of that handle. This is used when the DLL was loaded by some means other than dll_load/3.

dll_handle(?DllName,?DllHandle)

Enumerates the name-to-handle table.

This predicate run-time loads a DLL. The operating system handle is returned as an integer in Handle. The NewFlag variable will be 1 if this was the first time dll_load was called for this DLL, otherwise it will be 0.

dll_visi(+NameOrHandle,+Enable)

DLLs can be built to automatically manage their own visible definitions - adding them when the DLL is loaded and removing them when the DLL is unloaded. This predicate allows additional control over the process. It can be used when the DLL is not built to autoload or it can be used to remove the visible definitions associated with a DLL without unloading the DLL. NameOrHandle is as in dll_address/3. Enable is 1 to add the visible definitions or 0 to remove them. In order for this predicate to work the DLL must export its visible table definitions.

edit(+Filename)

Switches from the interpreter to a user-specified editor to edit the file specified as Filename. The file is reconsulted when the editor is exited.

end_choices(+Key)

See begin_choices/1.

eq(?X,?Y)

whether X and Y are the same data object.

erase(+Ref)

Removes the term stored under the given reference number and keeps track of the terms which are erased.

eraseall(+Key)

Removes all terms stored under the key.

errcode(-OldCode,+NewCode)

Returns the most recent syntax or file I/O error message code as OldCode, and sets the code to NewCode.

Looks up the address of a visible predicate for use by the call/2 predicate.

expand_term(+Term,-Newterm)

Transforms a term using definite clause grammar notation into its equivalent Prolog term.

expunge

Eliminates system references to deleted database terms.

fail

This goal always fails.

file_list(+Filename)

Saves the contents of the database to the file specified by Filename.

file_list(+Filename,+Name/Arity)

Saves the clauses specified by Name/Arity to the file specified by Filename.

fileerrors(?Old,?New)

Enables or disables DOS I/O error messages or checks the setting of these messages. To enable, set New to on. To disable, set New to off.

findall(?Term,+Goal,-List)

Collects all instances of Term where Goal is satisfiable and returns these instances of Term in an unordered list. All free variables are assumed to be existentially quantified.

float(?X)

Succeeds if X is a floating-point number.

float_text(?Number,?Text,?Format)

Converts a number to a string according to a Format specification or it converts a string to a floating- point number. The Format argument can be: general - trailing 0s suppressed; fixed(N) - fixed format with N digits to theright of the decimal point; scientific(N) - scientific format with N digits to the right of the decimal point.

flush

Removes all characters in the type-ahead buffer.

functor(?Struct,?Name,?Arity)

Returns a structure's name and arity.

gc

Restores unused stack space.

get(?Char)

get(+Handle,?Char)

Reads the next character from the standard input device or the specified file Handle, skipping non-printing characters, and unifies the ASCII value with Char.

get0(?Char)

get0(+Handle,?Char)

Reads the next character from the standard input device or specified file Hanlde and unifies the ASCII value with Char. The get0 predicate does not skip non-printing characters.

get0_noecho(?Char)

Reads the next character from the standard input device and unifies the ASCII value with Char. The get0_noecho predicate does not echo the character to the standard output device.

get_bit(+Bit,+Int,-Value)

Returns the Value (either 0 or 1) of a specified bit within an integer.

getEnvVar(+Variable,-/+Valve)

Allows you to get environment variable. If you do not specify a variable, it fails.

ground(?Term)

Succeeds if Term is ground (does not contain variables).

halt

Exits from the interpreter or from the compiled application.

halt(+Exit_code)

Exits from the interpreter or compiled program with the exit code specified by Exit_code.

hard_erase(+Ref)

Erases the database term with the specified key. Unlike erase, the hard_erase predicate does not keep track of erased terms.

ifthen(+P,+Q)

Executes goal Q if goal P succeeds. If goal P fails, ifthen succeeds without executing Q.

ifthenelse(+P,+Q,+R)

Executes goal Q if goal P succeeds, otherwise executes goal R.

inc(+N,-X)

Increments by 1 the number N to the value X.

instance(+Ref,-Term)

Returns the term associated with the reference number.

int_text(?Integer,?Text)

Converts an integer to a string or a string to an integer. If both instantiated, compares for equivalence.

integer(?X)

Succeeds if X is an integer.

X is E

Evaluates E and unifies the value with X.

key(+Key,-Ref)

Returns the reference number for the key.

key_count(+Key,-Count)

Returns a count of the number of terms stored under a database key.

keyb(-Ascii,-Scan)

keyb(-Ascii,-Scan,-/+Flags)

Reads the next character from the keyboard and returns the character's ASCII and Scan codes. If specified, a set of Flags is returned as the summation of the following:

1 right shifting key pressed

2 left shifting key pressed

4 control key pressed

8 Alt key pressed

16 Scroll Lock active

32 Num Lock active

64 Caps Lock active

128 Insert Mode is active

keyb_peek(-Ascii,-Scan)

keyb_peek(-Ascii,-Scan,-/+Flags)

Reads the next character from the keyboard and returns the character's ASCII and Scan codes, and does not remove the key from the buffer. If specified, a set of Flags can be returned detailing the state of other keyboard keys. (see keyb predicate)

keys(?Key)

Returns the name and arity for a key in the current data world. If Key is instantiated, succeeds if the key exists in the current data world.

keysort(+L1,-L2)

Sorts the list L1 in the standard order. Elements of the list must have the form: Key-Value. Duplicates are not merged. The sorted list is returned in L2.

leash(+Mode)

Leashes ports as specified by Mode, where Mode can be full, tight, half, or loose.

length(+List,-N)

Returns the length, N, of a character list.

list_text(?List,?String)

Converts a list of characters to a string, or converts an atom or string to a list of characters.

listing

Writes to standard output all the predicates in the current code world.

listing(+Name)

listing(+Name/Arity)

listing(+[Name/Arity,Name/Arity])

Writes to standard output all the clauses in the current code world for the specified predicate or list of predicates.

Loads the contents of files into the database.

lock

Used for "locking out" the ability for a Ctrl-Break to immediately terminate a program. The lock predicate adds 1 to the system's counting semaphore. Should be used in conjunction with unlock.

mkdir(+Path)

Creates a new directory. If Path is a full pathname (including drive name and directory names), then directory is created as specified. If Path is a name without a path, then the directory is created under the current directory.

mth_ref(+Ref,+Dir,-NewRef)

Returns either the previous (Dir = -1) or next (Dir = 1) database reference number to the specified Ref.

name(?Atom,?List)

Converts a list to an atom or converts an atom or integer to a list.

nl

nl(+Handle)

Writes a newline to the standard output device or specified file Handle.

nodebug

nodebug(-File)

Turns the debugger off. If specified, the name of the File that debugger output was formerly echoed to is returned.

nonvar(?X)

Succeeds if X is not an uninstantiated variable.

nospy(+Name)

nospy(+Name/Arity)

Removes a spy point from the specified predicate.

not(+P)

Fails if the goal P can be satisfied; succeeds if not.

notrace

notrace(+File)

Turns the debugger off. If specified, the name of the File that debugger output was formerly echoed to is returned. Same as nodebug.

nref(+Ref,-Next)

Returns the reference number of the next term in the chain of terms having the same key.

nth_char(+N,-String,-Char)

Returns the ASCII code of a character at offset N from the beginning of the string.

nth_ref(+Key,+N,-Ref)

Returns the reference number for the term some number of positions from the top of a chain of terms.

number(?X)

Succeeds when X is either an integer or a floating-point number.

op(+Prec,+Assoc,+Op)

Defines the precedence, position, and associativity of an operator.

open(-Handle,+Filename,+Access)

Opens an existing file. The Access argument can be: r - read; w - write; a - append; rw - read/write; ra - read/append.

p_open(-/+Handle,+Filename,+Access)

Opens the file specified by Filename. If the file isn't in the current directory, p_open searches for it in the directories indicated in the path specification in the autoexec.bat file.

p_open(-Handle,+Filename,+Type,+Pathvar)

Opens the file specified by Filename. Pathvar lets you include a path variable such as include, help or a path.

pfname(+FileName,?/+Prefix,?/+Name,?/+Extension,?/+HasExt)

Parses a file name into it's component path prefix, name and extension. HasExt is returned as either y orn to denote whether or not an extension was specified.

pref(+Ref,-Prev)

Returns the reference number for the previous term in a chain of terms.

put(+Char)

put(+Handle,+Char)

Writes the character to the standard output device or specified file Handle.

randomize(+Seed)

Resets the random number generator. The Seed argument is an integer.

Reads a term from the standard input device or specified file Handle.

Reads a text field from a file Handle where the length of the text is contained in the first byte (8-bits) read from the file.

Reads a text field from a file Handle where the length of the text is contained in the first word (16-bits) read from the file.

Reads a zero terminated text field from a file Handle.

Reads a zero terminated text field of a specified width from a file Handle.

Reads the next 8-bytes from a file Handle as an IEEE format float.

Reads the next 8-bits from a file Handle as an integer.

Reads the next 16-bits from a file Handle as an integer.

Reads the next 32-bits from a file Handle as an integer.

Reads a line from the file specified by Handle.

Reads a string of MaxLength characters from the standard input device or specified file Handle.

reconsult(+Filename)

Reads clauses into the database from a file, replacing any predicates that are already present in the database with those clauses that also occur in the file.

record_after(+Ref,?Term,-Newref)

Adds a term after Ref and returns the new reference number for the added term.

record_before(+Ref,?Term,-Newref)

Adds a term before Ref and returns the new reference number for the added term.

record_visi(+Goal,+Type,+Offset)

Low level access to the visible table. Type is 1-prolog, 2-eval, 3-evalpost, and offset is the address of the predicate. To remove the visible definition set Type=0.

recorda(+Key,?Term,-Ref)

Adds a term to the beginning of a predicate, and returns the reference number assigned to the added term.

recordb(+BTree,+Sort_Key,+Term)

Records terms in a B-tree.

recorded(+Key,?Term,-Ref)

Returns through backtracking the terms and associated reference numbers stored under a given key.

recorded(+Key,+Dir,?Term,-Ref)

Returns through backtracking the terms and associated reference numbers stored under a given key. The search order is specified with the Dir argument: 1 - forward; 0 - reverse.

recorded_nth(+Key,+N,-Term,-Ref)

Returns the Nth term stored under a database key and it's associated reference number.

recorded_ref(+Ref,+Dir,?Term,-Ref)

Returns through backtracking the terms and associated reference numbers stored at and prior to or after a specified database reference number. The search order is specified with the Dir argument: 1 - forward; 0 - reverse.

recorded_terms(+Key,?Match,-Terms)

Returns in a list all terms stored under a key that unify with the provided Match.

recorded_tro(+Key,?Term,-Ref)

Returns through backtracking the terms and associated reference numbers stored under a given key. The recorded_tro predicate uses tail recursion optimization and thus can be more efficient than the recorded predicate.

recordh(+Tablename,+Sortkey,+Term)

Records terms in a hash table.

recordz(+Key,?Term,-Ref)

Adds a term to the end of a predicate and returns the reference number assigned to the term.

ref(?X)

Succeeds when X is a database reference number.

refPartition(+Ref,-Partition)

Returns the partition a database ref is stored in.

removeallb(+BTree)

Deletes a B-tree.

removeallh(+Table_name)

Deletes a hash table.

removeb(+BTree,+Sort_key,?Term)

Deletes a term from a B-tree. If Term is uninstantiated, then the first term under Sort_key is deleted.

removeb(+BTree,+Sort_key)

Deletes all terms from a a B-tree that are associated with a particular Sort_key.

removeh(+Tablename,+Sortkey,?Term)

Deletes a term from a hash table. If Term is uninstantiated, then the first term under Sort_key is deleted.

rename(+Filename,+NewName)

Changes the name of a file.

repeat

Always succeeds, and when encountered during backtracking, always succeeds again.

replace(+Ref,+Term)

Replaces the term having the specified reference number with the term given by the Term argument.

replaceb(+BTree,+Sortkey,+Oldterm,+New_term)

Replaces the term at a specific position in a B-tree.

replaceh(+Hashtable,+Key,?Term0,+Term)

If Term0 is stored in the hash table under the given key, then it is replaced with Term.

reset_op

Returns the operator definitions to their default values.

resetspy

Clears all spy points.

restore

Eliminates all changes made to the database since the last time it was saved.

restore(+Name)

Restores the database specified by Name.

retract(+Clause)

Removes the first occurrence of the specified clause from the database.

retrieveb(+BTree,?Sort_key,?Term)

Returns a term from a B-tree.

retrieveb_keys(+BTree,-Keys)

Returns all of the Keys in a B-tree in a list.

retrievebnth(+BTree,+N,-Sortkey)

Returns the Nth key in a B-tree.

retrieveb_terms(+BTree,-Terms)

Returns all of the Terms in a B-tree in a list.

retrievebterms(+BTree,+Sortkey,-Terms)

Returns all of the Terms associated with a specified Sort_key in a B-tree in a list.

retrieveh(+Tablename,?Sortkey,?Term)

Returns a term from a hash table.

rmdir(+Path)

Deletes a directory.

save

Saves all changes made to the current database since the last time it was saved.

save(+Name)

Saves internal database file with the given Name.

scan_code(+Ascii,-Scan)

Returns the Scan code associated with an Ascii code.

searchPath(+PathSpec,+FileSpec,+Flags,-/+CompleteFileSpec)

Lets you look for a file on disk. The PathSpec tells it how to search. If you want to know the environment variable, you must specify the second flag bit. Flag 1 = Search current directory; Flag 2 = PathSpec is an environment variable; Flag 3 = Search the application directory.

see(+Filename)

Opens a file for reading and makes it the current input device.

see_h(+Handle)

The previously open file specified by Handle becomes the current input file.

seeing(?Filename)

Returns the name of the file that was opened for reading by see. If you used see_h, then seeing will fail.

seek(+Handle,+Offset,+Method,-NewLoc)

Moves the internal file pointer to a specific location within a file. The Offset represents a relative location within the file in bytes. The Method indicates point from which Offset is calculated and can be: bof - beginning of file; eof - end of file; current - current location.

seen

Ends input from the current open file and closes the file.

set_bit(+Bit,+NewValue,+OldInt,-NewInt,-OldValue)

Sets the value of a bit in an integer, returning the new integer and the old value of the bit.

Set a number of bits defined with a Mask to the values defined with Data in an integer.

setof(?Term,+Goal,-Set)

Collects all instances of Term where the Goal is satisfiable and returns those instances in an ordered list without duplicates (Set).

shell

Allows you to run an OS/2 command interpreter while maintaining your current program state. Type exit to return. This predicate always succeeds.

shell(+Command)

Executes an command and succeeds.

skip(+Char)

Reads and skips characters from the standard input device until Char is found.

skip(+Handle,+Char)

Reads and skips characters from a file until Char is found.

sort(+L1,-L2)

Sorts the list L1 in the standard order, merging duplicates, and returns the sorted list in L2.

sortkey(+Key)

Sorts the terms contained in a database key.

spy(+Name)

spy(+Name/Arity)

Specifies a predicate as a spy point for debugging.

statistics

Displays a window which lists all of the Arity/Prolog32 system usage statistics. Also available in vanilla mode.

statistics(+Info,-Struct)

Returns information about Arity/Prolog32 system usage. The Info argument can be stacks, database, local, global, trail, garbage and version.

stdin(+Filename,+Goal)

Redirects standard input for the duration of the goal.

stdinout(+InFile,+OutFile,+Goal)

Redirects the standard input and output for the duration of the goal.

stdout(+Filename,+Goal)

Redirects the standard output for the duration of the goal.

string(?X)

Succeeds if X is a string.

string_length(+String,?Length)

Returns the length of the string. If Length is instantiated, succeeds if Length is the length of String.

string_lower(+Text,-Lower)

Converts a piece of Text to the equivalent lower-case string.

string_search(+SubString,+String,-Location)

Searches a string for the substring and returns the starting point of the string to the Location argument. Location is offset from 0. This predicate can backtrack.

string_search(+Case,+SubString,+String,-Location)

Searches a string for the substring and returns the starting point of the string to the Location argument. Location is offset from 0. If Case is set to 0, the search is case sensitive. If Case is set to 1, the search is not case sensitive. This predicate can backtrack.

string_term(?String,?Term)

Converts a string or atom to a term or converts a term to a string.

string_termq(?/+Quotestring,?/+Term)

Version of string_term that works like writeq.

string_upper(+Text,-Lower)

Converts a piece of Text to the equivalent lower-case string.

substring(+InString,+N,+Length,-OutString)

Extracts a substring from a string. The N argument identifies the beginning of the substring (string characters are numbered from 0). The Length argument indicates the length of the substring.

syntaxerrors(?Old,?New)

Enables or disables Arity/Prolog32 syntax errors or checks the current setting of these messages.

system(?Predicate)

Determines whether Predicate is an evaluable predicate. If instantiated, Predicate can be name or name/arity.

system(?Predicate,-Old,+New)

This predicate allows you to disable a visible definition. Use as a get / set where 'on' means that the predicate is disabled.

sysflag(+FlagNo,-Old,+New)

Gets / sets the value of system flags; Only one system flag is currently available for users: safesave enabled: FlagNo = 11, default off

tab(+Num)

Writes a given number of spaces to the standard output device. The Num argument must be in the range 0-255.

tab(+Handle,+Num)

Writes a given number of spaces to the file. The Num argument must be in the range 0-255.

tell(+Filename)

Opens a file for writing and makes it the current output file.

tell_h(+Handle)

Writes to the previously opened file specified by Handle.

telling(?Filename)

Returns the name of the file that was opened for writing by tell. If tell_h was used, telling fails.

term2dbcs(+Term,+Ptr,+MaxLen,-ActLen)

Encodes Term as a C string at Ptr. If the length of the encoded string is larger than MaxLen then the predicate fails doing no work. The actual length written is returned in ActLen. Note that the string that is created is not null terminated and may contain embedded nulls.

term2dbs(+Term,-DBString)

Encodes Term as the Prolog string DBString.

term_concat(+Functor,+Args,-Term)

Returns a Term created from the provided functor and arguments.

time(?time(Hours,Minutes,Seconds,Hundredths))

Returns or sets the system clock.

told

Closes the file that is currently open for writing.

trace

Turns the debugger on, initialy set to creep mode.

trace(+File)

Turns on tracing, creates new file and stores tracing information in the file you specified.

true

This goal always succeeds.

unlock

Subtracts 1 from the system's counting semaphore. Used in conjunction with lock to isolate a portion of code so that Ctrl-Break does terminate the program until processing of that portion is complete.

var(?X)

Determines whether X is an uninstantiated variable.

varnames(?Term)

Assigns a printable name to each variable in a term.

what_btrees(-Btree)

Returns, through backtracking, the names of each of the existing B-trees.

what_worlds(?X)

Returns, through backtracking, the name of the worlds that currently exist.

workspace(-OldWorkspaceNumber,+NewWorkspaceNumber)

Gets / sets the current database workspace number (0 ..3).

write(+Term)

Writes the term to the standard output device.

write(+Handle,+Term)

Writes the term to the specified file.

write_ascib(+Handle,+Text)

Writes a Text field to a file Handle preceeded by the length in a single byte (8-bits).

write_asciw(+Handle,+Text)

Writes a Text field to a file Handle preceeded by the length in a single word (16-bits).

write_asciz(+Handle,+Text)

Writes a zero terminated text field to a file Handle.

writeascizfield(+Handle,+Width,+Text)

Writes a zero terminated text field of a specified width to a file Handle.

write_float(+Handle,+Float)

Writes a floating-point number to a file Handle in an 8-byte format.

write_int8(+Handle,+Integer)

Writes an integer to a file Handle in a 8-bit format.

write_int16(+Handle,+Integer)

Writes an integer to a file Handle in a 16-bit format.

write_int32(+Handle,+Integer)

Writes an integer to a file Handle in a 32-bit format.

write_key(+Key,+File,+Backup)

Writes the text key to ASCII file and if Backup is equal to 1 and there currently exists a version of File, it saves the old file as a .BAK file.

writeq(+Term)

Writes the term to the standard output device, and quotes atoms and functors as necessary for the term to be readable as a Prolog term.

writeq(+Handle,+Term)

Writes the term to the file specified, and quotes atoms and functors as necessary for the term to be readable as a Prolog term.