The predicate summary is used by the Prolog predicate apropos/1 to suggest predicates from a keyword.
| !/0 | Cut (discard choicepoints) |
| !/1 | Cut block. See block/3 |
| #>/2 | Greater than constraint |
| #</2 | Less than constraint |
| #>=/2 | Greater or equal constraint |
| #=</2 | Less of equal constraint |
| #\=/2 | Non-equal constraint |
| #=/2 | Equality constraint |
| #<=>/2 | Constraint equivalence |
| #<=/2 | Constraint implication to the left |
| #=>/2 | Constraint implication to the right |
| ,/2 | Conjunction of goals |
| ->/2 | If-then-else |
| *->/2 | Soft-cut |
| ./2 | Consult. Also list constructor |
| ;/2 | Disjunction of goals. Same as |/2 |
| </2 | Arithmetic smaller |
| =/2 | Unification |
| =../2 | ``Univ.'' Term to list conversion |
| =:=/2 | Arithmetic equal |
| =</2 | Arithmetic smaller or equal |
| ==/2 | Identical |
| =@=/2 | Structural identical |
| =\=/2 | Arithmetic not equal |
| >/2 | Arithmetic larger |
| >=/2 | Arithmetic larger or equal |
| ?=/2 | Test of terms can be compared now |
| @</2 | Standard order smaller |
| @=</2 | Standard order smaller or equal |
| @>/2 | Standard order larger |
| @>=/2 | Standard order larger or equal |
| \+/1 | Negation by failure. Same as not/1 |
| \=/2 | Not unifyable |
| \==/2 | Not identical |
| \=@=/2 | Not structural identical |
| ^/2 | Existential quantification (bagof/3, setof/3) |
| |/2 | Disjunction of goals. Same as ;/2 |
| abolish/1 | Remove predicate definition from the database |
| abolish/2 | Remove predicate definition from the database |
| abort/0 | Abort execution, return to top level |
| absolute_file_name/2 | Get absolute path name |
| absolute_file_name/3 | Get absolute path name with options |
| access_file/2 | Check access permissions of a file |
| acyclic_term/1 | Test term for cycles |
| add_import_module/3 | Add module to the auto-import list |
| all_different/1 | Constraint all values to be unique |
| append/1 | Append to a file |
| apply/2 | Call goal with additional arguments |
| apropos/1 | library(online_help)
Search manual |
| arg/3 | Access argument of a term |
| arithmetic_function/1 | Register an evaluable function |
| assert/1 | Add a clause to the database |
| assert/2 | Add a clause to the database, give reference |
| asserta/1 | Add a clause to the database (first) |
| asserta/2 | Add a clause to the database (first) |
| assertz/1 | Add a clause to the database (last) |
| assertz/2 | Add a clause to the database (last) |
| assume/1 | Make assertions about your program |
| attach_console/0 | Attach I/O console to thread |
| attr_unify_hook/2 | Attributed variable unification hook |
| attr_portray_hook/2 | Attributed variable print hook |
| attvar/1 | Type test for attributed variable |
| at_end_of_stream/0 | Test for end of file on input |
| at_end_of_stream/1 | Test for end of file on stream |
| at_halt/1 | Register goal to run at halt/1 |
| at_initialization/1 | Register goal to run at start-up |
| atom/1 | Type check for an atom |
| atom_chars/2 | Convert between atom and list of characters |
| atom_codes/2 | Convert between atom and list of characters codes |
| atom_length/2 | Determine length of an atom |
| atom_prefix/2 | Test for start of atom |
| atom_number/2 | Convert between atom and number |
| atom_to_term/3 | Convert between atom and term |
| atomic/1 | Type check for primitive |
| autoload/0 | Autoload all predicates now |
| b_getval/2 | Fetch backtrackable global variable |
| b_setval/2 | Assign backtrackable global variable |
| bagof/3 | Find all solutions to a goal |
| between/3 | Integer range checking/generating |
| block/3 | Start a block (`catch'/`throw') |
| break/0 | Start interactive toplevel |
| call/1 | Call a goal |
| call/[2..] | Call with additional arguments |
| call_cleanup/3 | Guard a goal with a cleaup-handler |
| call_cleanup/2 | Guard a goal with a cleaup-handler |
| call_shared_object_function/2 | UNIX: Call C-function in shared (.so) file |
| call_with_depth_limit/3 | Prove goal with bounded depth |
| callable/1 | Test for atom or compound term |
| catch/3 | Call goal, watching for exceptions |
| char_code/2 | Convert between character and character code |
| char_conversion/2 | Provide mapping of input characters |
| char_type/2 | Classify characters |
| character_count/2 | Get character index on a stream |
| chdir/1 | Compatibility: change working directory |
| chr_show_store/1 | List suspended CHR constraints |
| chr_trace/0 | Start CHR tracer |
| chr_notrace/0 | Stop CHR tracer |
| chr_leash/1 | Define CHR leashed ports |
| clause/2 | Get clauses of a predicate |
| clause/3 | Get clauses of a predicate |
| clause_property/2 | Get properties of a clause |
| close/1 | Close stream |
| close/2 | Close stream (forced) |
| close_dde_conversation/1 | Win32: Close DDE channel |
| close_shared_object/1 | UNIX: Close shared library (.so file) |
| compare/3 | Compare, using a predicate to determine the order |
| compile_predicates/1 | Compile dynamoc code to static |
| compiling/0 | Is this a compilation run? |
| compound/1 | Test for compound term |
| atom_concat/3 | Append two atoms |
| code_type/2 | Classify a character-code |
| concat_atom/2 | Append a list of atoms |
| concat_atom/3 | Append a list of atoms with separator |
| consult/1 | Read (compile) a Prolog source file |
| context_module/1 | Get context module of current goal |
| convert_time/8 | Break time stamp into fields |
| convert_time/2 | Convert time stamp to string |
| copy_stream_data/2 | Copy all data from stream to stream |
| copy_stream_data/3 | Copy n bytes from stream to stream |
| copy_term/2 | Make a copy of a term |
| current_arithmetic_function/1 | Examine evaluable functions |
| current_atom/1 | Examine existing atoms |
| current_blob/2 | Examine typed blobs |
| current_char_conversion/2 | Query input character mapping |
| current_flag/1 | Examine existing flags |
| current_foreign_library/2 | library(shlib)
Examine loaded shared libraries (.so files) |
| current_format_predicate/2 | Enumerate user-defined format codes |
| current_functor/2 | Examine existing name/arity pairs |
| current_input/1 | Get current input stream |
| current_key/1 | Examine existing database keys |
| current_module/1 | Examine existing modules |
| current_module/2 | Examine existing modules |
| current_mutex/3 | Examine existing mutexes |
| current_op/3 | Examine current operator declarations |
| current_output/1 | Get the current output stream |
| current_predicate/1 | Examine existing predicates (ISO) |
| current_predicate/2 | Examine existing predicates |
| current_signal/3 | Current software signal mapping |
| current_stream/3 | Examine open streams |
| current_thread/2 | Examine Prolog threads |
| cyclic_term/1 | Test term for cycles |
| dde_current_connection/2 | Win32: Examine open DDE connections |
| dde_current_service/2 | Win32: Examine DDE services provided |
| dde_execute/2 | Win32: Execute command on DDE server |
| dde_register_service/2 | Win32: Become a DDE server |
| dde_request/3 | Win32: Make a DDE request |
| dde_poke/3 | Win32: POKE operation on DDE server |
| dde_unregister_service/1 | Win32: Terminate a DDE service |
| debug/0 | Test for debugging mode |
| debug/1 | Select topic for debugging |
| debug/3 | Print debugging message on topic |
| debug_control_hook/1 | (hook) Extend spy/1, etc. |
| debugging/0 | Show debugger status |
| debugging/1 | Test where we are debugging topic |
| default_module/2 | Get the default modules of a module |
| del_attr/2 | Delete attribute from variable |
| delete_directory/1 | Remove a folder from the file system |
| delete_file/1 | Remove a file from the file system |
| delete_import_module/2 | Remove module from import list |
| deterministic/1 | Test deterministicy of current clause |
| dif/2 | Contrain two terms to be different |
| discontiguous/1 | Indicate distributed definition of a predicate |
| downcase_atom/2 | Convert atom to lower-case |
| duplicate_term/2 | Create a copy of a term |
| dwim_match/2 | Atoms match in ``Do What I Mean'' sense |
| dwim_match/3 | Atoms match in ``Do What I Mean'' sense |
| dwim_predicate/2 | Find predicate in ``Do What I Mean'' sense |
| dynamic/1 | Indicate predicate definition may change |
| edit/0 | Edit current script- or associated file |
| edit/1 | Edit a file, predicate, module (extensible) |
| ensure_loaded/1 | Consult a file if that has not yet been done |
| erase/1 | Erase a database record or clause |
| eval_license/0 | Evaluate licenses of loaded modules |
| exception/3 | (hook) Handle runtime exceptions |
| exists_directory/1 | Check existence of directory |
| exists_file/1 | Check existence of file |
| exit/2 | Exit from named block. See block/3 |
| expand_answer/2 | Expand answer of query |
| expand_file_name/2 | Wildcard expansion of file names |
| expand_file_search_path/2 | Wildcard expansion of file paths |
| expand_goal/2 | Compiler: expand goal in clause-body |
| expand_query/4 | Expanded entered query |
| expand_term/2 | Compiler: expand read term into clause(s) |
| explain/1 | library(explain)
Explain argument |
| explain/2 | library(explain)
2nd argument is explanation of first |
| export/1 | Export a predicate from a module |
| export_list/2 | List of public predicates of a module |
| fail/0 | Always false |
| fail/1 | Immediately fail named block. See block/3 |
| current_prolog_flag/2 | Get system configuration parameters |
| file_base_name/2 | Get file part of path |
| file_directory_name/2 | Get directory part of path |
| file_name_extension/3 | Add, remove or test file extensions |
| file_search_path/2 | Define path-aliases for locating files |
| fileerrors/2 | Do/Don't warn on file errors |
| findall/3 | Find all solutions to a goal |
| flag/3 | Simple global variable system |
| float/1 | Type check for a floating point number |
| flush_output/0 | Output pending characters on current stream |
| flush_output/1 | Output pending characters on specified stream |
| forall/2 | Prove goal for all solutions of another goal |
| format/1 | Formatted output |
| format/2 | Formatted output with arguments |
| format/3 | Formatted output on a stream |
| format_predicate/2 | Program format/[1,2] |
| term_variables/2 | Find unbound variables in a term |
| term_variables/3 | Find unbound variables in a term |
| freeze/2 | Delay execution until variable is bound |
| frozen/2 | Query delayed goals on var |
| functor/3 | Get name and arity of a term or construct a term |
| garbage_collect/0 | Invoke the garbage collector |
| garbage_collect_atoms/0 | Invoke the atom garbage collector |
| gensym/2 | Generate unique atoms from a base |
| get/1 | Read first non-blank character |
| get/2 | Read first non-blank character from a stream |
| get0/1 | Read next character |
| get0/2 | Read next character from a stream |
| get_attr/3 | Fetch named attribute from a variable |
| get_attrs/2 | Fetch all attributes of a variable |
| get_byte/1 | Read next byte (ISO) |
| get_byte/2 | Read next byte from a stream (ISO) |
| get_char/1 | Read next character as an atom (ISO) |
| get_char/2 | Read next character from a stream (ISO) |
| get_code/1 | Read next character (ISO) |
| get_code/2 | Read next character from a stream (ISO) |
| get_single_char/1 | Read next character from the terminal |
| get_time/1 | Get current time |
| getenv/2 | Get shell environment variable |
| goal_expansion/2 | Hook for macro-expanding goals |
| ground/1 | Verify term holds no unbound variables |
| guitracer/0 | Install hooks for the graphical debugger |
| halt/0 | Exit from Prolog |
| halt/1 | Exit from Prolog with status |
| hash/1 | Index predicate using a hash-table |
| hash_term/2 | Hash-value of ground term |
| help/0 | Give help on help |
| help/1 | Give help on predicates and show parts of manual |
| help_hook/1 | (hook) User-hook in the help-system |
| ignore/1 | Call the argument, but always succeed |
| import/1 | Import a predicate from a module |
| import_module/2 | Query import modules |
| in/2 | Define interval for variable |
| include/1 | Include a file with declarations |
| index/1 | Change clause indexing |
| initialization/1 | Initialization directive |
| int_to_atom/2 | Convert from integer to atom |
| int_to_atom/3 | Convert from integer to atom (non-decimal) |
| integer/1 | Type check for integer |
| interactor/0 | Start new thread with console and toplevel |
| is/2 | Evaluate arithmetic expression |
| is_absolute_file_name/1 | True if arg defines an absolute path |
| is_list/1 | Type check for a list |
| keysort/2 | Sort, using a key |
| label/1 | Solve constraints for variables |
| last/2 | Last element of a list |
| leash/1 | Change ports visited by the tracer |
| length/2 | Length of a list |
| library_directory/1 | (hook) Directories holding Prolog libraries |
| license/1 | Define license for current file |
| license/2 | Define license for named module |
| limit_stack/2 | Limit stack expansion |
| line_count/2 | Line number on stream |
| line_position/2 | Character position in line on stream |
| list_debug_topics/0 | List registered topics for debugging |
| list_to_set/2 | Remove duplicates from a list |
| listing/0 | List program in current module |
| listing/1 | List predicate |
| load_files/2 | Load source files with options |
| load_foreign_library/1 | library(shlib)
Load shared library (.so file) |
| load_foreign_library/2 | library(shlib)
Load shared library (.so file) |
| make/0 | Reconsult all changed source files |
| make_directory/1 | Create a folder on the file system |
| make_fat_filemap/1 | Win32: Create file containing non-FAT filenames |
| make_library_index/1 | Create autoload file INDEX.pl |
| make_library_index/2 | Create selective autoload file INDEX.pl |
| maplist/2 | Apply predicate on all elements |
| maplist/3 | Map elements pairwise |
| maplist/4 | Map triples of elements |
| memberchk/2 | Deterministic member/2 |
| merge/3 | Merge two sorted lists |
| merge_set/3 | Merge two sorted sets |
| message_hook/3 | Intercept print_message/2 |
| message_queue_create/1 | Create queue for thread communication |
| message_queue_destroy/1 | Destroy queue for thread communication |
| message_to_string/2 | Translate message-term to string |
| meta_predicate/1 | Quintus compatibility |
| module/1 | Query/set current type-in module |
| module/2 | Declare a module |
| module_transparent/1 | Indicate module based meta predicate |
| msort/2 | Sort, do not remove duplicates |
| multifile/1 | Indicate distributed definition of predicate |
| mutex_create/1 | Create a thread-synchronisation device |
| mutex_destroy/1 | Destroy a mutex |
| mutex_lock/1 | Become owner of a mutex |
| mutex_statistics/0 | Print statistics on mutex usage |
| mutex_trylock/1 | Become owner of a mutex (non-blocking) |
| mutex_unlock/1 | Release ownership of mutex |
| mutex_unlock_all/0 | Release ownership of all mutexes |
| name/2 | Convert between atom and list of character codes |
| nb_current/2 | Enumerate non-backtrackable global variables |
| nb_delete/1 | Delete a non-backtrackable global variable |
| nb_getval/2 | Fetch non-backtrackable global variable |
| nb_linkarg/3 | Non-backtrackable assignment to term |
| nb_linkval/2 | Assign non-backtrackable global variable |
| nb_setarg/3 | Non-backtrackable assignment to term |
| nb_setval/2 | Assign non-backtrackable global variable |
| nl/0 | Generate a newline |
| nl/1 | Generate a newline on a stream |
| nodebug/0 | Disable debugging |
| nodebug/1 | Disable debug-topic |
| noguitracer/0 | Disable the graphical debugger |
| nonvar/1 | Type check for bound term |
| noprofile/1 | Hide (meta) predicate for the profiler |
| noprotocol/0 | Disable logging of user interaction |
| nospy/1 | Remove spy point |
| nospyall/0 | Remove all spy points |
| not/1 | Negation by failure (argument not provable). Same as \+/1 |
| notrace/0 | Stop tracing |
| notrace/1 | Do not debug argument goal |
| nth_clause/3 | N-th clause of a predicate |
| number/1 | Type check for integer or float |
| number_chars/2 | Convert between number and one-char atoms |
| number_codes/2 | Convert between number and character codes |
| numbervars/3 | Number unbound variables of a term |
| numbervars/4 | Number unbound variables of a term |
| on_signal/3 | Handle a software signal |
| once/1 | Call a goal deterministically |
| op/3 | Declare an operator |
| open/3 | Open a file (creating a stream) |
| open/4 | Open a file (creating a stream) |
| open_dde_conversation/3 | Win32: Open DDE channel |
| open_null_stream/1 | Open a stream to discard output |
| open_resource/3 | Open a program resource as a stream |
| open_shared_object/2 | UNIX: Open shared library (.so file) |
| open_shared_object/3 | UNIX: Open shared library (.so file) |
| pce_dispatch/1 | Run XPCE GUI in seperate thread |
| pce_call/1 | Run goal in XPCE GUI thread |
| peek_byte/1 | Read byte without removing |
| peek_byte/2 | Read byte without removing |
| peek_char/1 | Read character without removing |
| peek_char/2 | Read character without removing |
| peek_code/1 | Read character-code without removing |
| peek_code/2 | Read character-code without removing |
| phrase/2 | Activate grammar-rule set |
| phrase/3 | Activate grammar-rule set (returning rest) |
| please/3 | Query/change environment parameters |
| plus/3 | Logical integer addition |
| portray/1 | (hook) Modify behaviour of print/1 |
| portray_clause/1 | Pretty print a clause |
| portray_clause/2 | Pretty print a clause to a stream |
| predicate_property/2 | Query predicate attributes |
| predsort/3 | Sort, using a predicate to determine the order |
| preprocessor/2 | Install a preprocessor before the compiler |
| print/1 | Print a term |
| print/2 | Print a term on a stream |
| print_message/2 | Print message from (exception) term |
| print_message_lines/3 | Print message to stream |
| profile/1 | Obtain execution statistics |
| profile/3 | Obtain execution statistics |
| profile_count/3 | Obtain profile results on a predicate |
| profiler/2 | Obtain/change status of the profiler |
| prolog/0 | Run interactive toplevel |
| prolog_choice_attribute/3 | Examine the choice-point stack |
| prolog_current_frame/1 | Reference to goal's environment stack |
| prolog_edit:locate/2 | Locate targets for edit/1 |
| prolog_edit:locate/3 | Locate targets for edit/1 |
| prolog_edit:edit_source/1 | Call editor for edit/1 |
| prolog_edit:edit_command/2 | Specify editor activation |
| prolog_edit:load/0 | Load edit/1 extensions |
| prolog_file_type/2 | Define meaning of file extension |
| prolog_frame_attribute/3 | Obtain information on a goal environment |
| prolog_ide/1 | Program access to the development enviroment |
| prolog_list_goal/1 | (hook) Intercept tracer 'L' command |
| prolog_load_context/2 | Context information for directives |
| prolog_load_file/2 | (hook) Program load_files/2 |
| prolog_skip_level/2 | Indicate deepest recursion to trace |
| prolog_to_os_filename/2 | Convert between Prolog and OS filenames |
| prolog_trace_interception/4 | library(user)
Intercept the Prolog tracer |
| prompt1/1 | Change prompt for 1 line |
| prompt/2 | Change the prompt used by read/1 |
| protocol/1 | Make a log of the user interaction |
| protocola/1 | Append log of the user interaction to file |
| protocolling/1 | On what file is user interaction logged |
| put/1 | Write a character |
| put/2 | Write a character on a stream |
| put_attr/3 | Put attribute on a variable |
| put_attrs/2 | Set/replace all attributes on a variable |
| put_byte/1 | Write a byte |
| put_byte/2 | Write a byte on a stream |
| put_char/1 | Write a character |
| put_char/2 | Write a character on a stream |
| put_code/1 | Write a character-code |
| put_code/2 | Write a character-code on a stream |
| qcompile/1 | Compile source to Quick Load File |
| qsave_program/1 | Create runtime application |
| qsave_program/2 | Create runtime application |
| read/1 | Read Prolog term |
| read/2 | Read Prolog term from stream |
| read_clause/1 | Read clause |
| read_clause/2 | Read clause from stream |
| read_history/6 | Read using history substitution |
| read_link/3 | Read a symbolic link |
| read_pending_input/3 | Fetch buffered input from a stream |
| read_term/2 | Read term with options |
| read_term/3 | Read term with options from stream |
| recorda/2 | Record term in the database (first) |
| recorda/3 | Record term in the database (first) |
| recorded/2 | Obtain term from the database |
| recorded/3 | Obtain term from the database |
| recordz/2 | Record term in the database (last) |
| recordz/3 | Record term in the database (last) |
| redefine_system_predicate/1 | Abolish system definition |
| reload_library_index/0 | Force reloading the autoload index |
| rename_file/2 | Change name of file |
| repeat/0 | Succeed, leaving infinite backtrack points |
| require/1 | This file requires these predicates |
| reset_profiler/0 | Clear statistics obtained by the profiler |
| resource/3 | Declare a program resource |
| retract/1 | Remove clause from the database |
| retractall/1 | Remove unifying clauses from the database |
| same_file/2 | Succeeds if arguments refer to same file |
| see/1 | Change the current input stream |
| seeing/1 | Query the current input stream |
| seek/4 | Modify the current position in a stream |
| seen/0 | Close the current input stream |
| set_input/1 | Set current input stream from a stream |
| set_output/1 | Set current output stream from a stream |
| set_prolog_IO/3 | Prepare streams for interactive session |
| set_prolog_flag/2 | Define a system feature |
| set_stream/2 | Set stream attribute |
| set_stream_position/2 | Seek stream to position |
| set_tty/2 | Set `tty' stream |
| setarg/3 | Destructive assignment on term |
| setenv/2 | Set shell environment variable |
| setof/3 | Find all unique solutions to a goal |
| sformat/2 | Format on a string |
| sformat/3 | Format on a string |
| shell/0 | Execute interactive subshell |
| shell/1 | Execute OS command |
| shell/2 | Execute OS command |
| show_profile/1 | Show results of the profiler |
| show_profile/2 | Show results of the profiler |
| size_file/2 | Get size of a file in characters |
| skip/1 | Skip to character in current input |
| skip/2 | Skip to character on stream |
| rl_add_history/1 | Add line to readline(3) history |
| rl_read_init_file/1 | Read readline(3) init file |
| sleep/1 | Suspend execution for specified time |
| sort/2 | Sort elements in a list |
| source_file/1 | Examine currently loaded source files |
| source_file/2 | Obtain source file of predicate |
| source_location/2 | Location of last read term |
| spy/1 | Force tracer on specified predicate |
| stack_parameter/4 | Some systems: Query/Set runtime stack parameter |
| statistics/0 | Show execution statistics |
| statistics/2 | Obtain collected statistics |
| stream_property/2 | Get stream properties |
| string/1 | Type check for string |
| string_concat/3 | atom_concat/3 for strings |
| string_length/2 | Determine length of a string |
| string_to_atom/2 | Conversion between string and atom |
| string_to_list/2 | Conversion between string and list of character codes |
| strip_module/3 | Extract context module and term |
| style_check/1 | Change level of warnings |
| sub_atom/5 | Take a substring from an atom |
| sublist/3 | Determine elements that meet condition |
| sub_string/5 | Take a substring from a string |
| succ/2 | Logical integer successor relation |
| swritef/2 | Formatted write on a string |
| swritef/3 | Formatted write on a string |
| tab/1 | Output number of spaces |
| tab/2 | Output number of spaces on a stream |
| tell/1 | Change current output stream |
| telling/1 | Query current output stream |
| term_expansion/2 | (hook) Convert term before compilation |
| term_to_atom/2 | Convert between term and atom |
| thread_at_exit/1 | Register goal to be called at exit |
| thread_create/3 | Create a new Prolog task |
| thread_detach/1 | Make thread cleanup after completion |
| thread_exit/1 | Terminate Prolog task with value |
| thread_get_message/1 | Wait for message |
| thread_get_message/2 | Wait for message in a queue |
| thread_join/2 | Wait for Prolog task-completion |
| thread_local/1 | Declare thread-specific clauses for a predicate |
| thread_peek_message/1 | Test for message |
| thread_peek_message/2 | Test for message in a queue |
| thread_self/1 | Get identifier of current thread |
| thread_send_message/2 | Send message to another thread |
| thread_setconcurrency/2 | Number of active threads |
| thread_signal/2 | Execute goal in another thread |
| thread_statistics/3 | Get statistics of another thread |
| threads/0 | List running threads |
| throw/1 | Raise an exception (see catch/3) |
| time/1 | Determine time needed to execute goal |
| time_file/2 | Get last modification time of file |
| tmp_file/2 | Create a temporary filename |
| told/0 | Close current output |
| trace/0 | Start the tracer |
| trace/1 | Set trace-point on predicate |
| trace/2 | Set/Clear trace-point on ports |
| tracing/0 | Query status of the tracer |
| trim_stacks/0 | Release unused memory resources |
| true/0 | Succeed |
| tty_get_capability/3 | Get terminal parameter |
| tty_goto/2 | Goto position on screen |
| tty_put/2 | Write control string to terminal |
| tty_size/2 | Get row/column size of the terminal |
| ttyflush/0 | Flush output on terminal |
| unify_with_occurs_check/2 | Logically sound unification |
| unifyable/3 | Determing binding required for unification |
| unix/1 | OS interaction |
| unknown/2 | Trap undefined predicates |
| unload_foreign_library/1 | library(shlib)
Detach shared library (.so file) |
| unsetenv/1 | Delete shell environment variable |
| upcase_atom/2 | Convert atom to upper-case |
| use_module/1 | Import a module |
| use_module/2 | Import predicates from a module |
| var/1 | Type check for unbound variable |
| visible/1 | Ports that are visible in the tracer |
| volatile/1 | Predicates that are not saved |
| wait_for_input/3 | Wait for input with optional timeout |
| when/2 | Execute goal when condition becomes true |
| wildcard_match/2 | Csh(1) style wildcard match |
| win_exec/2 | Win32: spawn Windows task |
| win_has_menu/0 | Win32: true if console menu is available |
| win_insert_menu/2 | plwin.exe: add menu |
| win_insert_menu_item/4 | plwin.exe: add item to menu |
| win_shell/2 | Win32: open document through Shell |
| win_shell/3 | Win32: open document through Shell |
| win_registry_get_value/3 | Win32: get registry value |
| win_window_pos/1 | Win32: change size and position of window |
| window_title/2 | Win32: change title of window |
| with_mutex/2 | Run goal while holding mutex |
| working_directory/2 | Query/change CWD |
| write/1 | Write term |
| write/2 | Write term to stream |
| writeln/1 | Write term, followed by a newline |
| write_canonical/1 | Write a term with quotes, ignore operators |
| write_canonical/2 | Write a term with quotes, ignore operators on a stream |
| write_term/2 | Write term with options |
| write_term/3 | Write term with options to stream |
| writef/1 | Formatted write |
| writef/2 | Formatted write on stream |
| writeq/1 | Write term, insert quotes |
| writeq/2 | Write term, insert quotes on stream |