Prolog Flags¶

Flags can be used to configure and to query the Prolog engine.

• YAP Thread-local flags

• YAP Thread-shared or Global flags

Inquiring and setting YAP state.

• create_prolog_flag/4
• prolog_flag/4
• prolog_flag_property/2

• [no_source

• [source

• set_prolog_flag/2

• current_prolog_flag/2

Define:¶

1. INIT_FLAGS:

1. YAP_FLAG:

1. END_FLAG:

1. PROLOG_FLAG_PROPERTY_DEFS:

1. PAR:

1. PAR:

Functions:¶

1. Term ro(Term inp):

1. Term nat(Term inp):

1. Term isatom(Term inp):

1. Term booleanFlag(Term inp):

1. static Term list_option(Term inp):

1. static Term argv(Term inp):

1. static Term os_argv(Term inp):

1. static bool agc_threshold(Term inp):

1. static bool gc_margin(Term inp):

1. static Term executable(Term inp):

1. static Term sys_thread_id(Term inp):

1. static Term sys_pid(Term inp):

1. static bool mkprompt(Term inp):

1. static Term indexer(Term inp):

1. static Term stream(Term inp):

1. static bool getenc(Term inp):

1. static bool typein(Term inp):

1. static bool set_error_stream(Term inp):

1. static bool set_input_stream(Term inp):

1. static bool set_output_stream(Term inp):

1. static bool dollar_to_lc(Term inp):

1. static bool setSignals(Term inp): : set or reset signal handlers.

The act is only performed if the flag changed values.

inpWhether to enable or disable return:
always true

1. static void newFlag(Term fl, Term val):

1. static Int set_prolog_flag(USES_REGS1):

1. static Term compiling(Term inp):

1. Term aro(Term inp):

1. static Term mkplus(Term val):

1. Term febooleanFlag(Term inp):

1. static Term quote(mod_entry_flags_t qt):

1. static Term snglq(Term val):

1. static Term dblq(Term val):

1. static Term bckq(Term val):

1. static Term multil(Term val):

1. static Term undefph(Term val):

1. Term synerr(Term inp):

1. static Term isaccess(Term inp):

1. static Term isground(Term inp):

1. static Term flagscope(Term inp):

1. static Term mk_argc_list(USES_REGS1):

1. static Term mk_os_argc_list(USES_REGS1):

1. static FlagEntry * GetFlagProp(Atom a):

1. static void initFlag(flag_info *f, int fnum, bool global):

1. static Int cont_current_prolog_flag(USES_REGS1):

1. static Int current_prolog_flag(USES_REGS1):

1. bool Yap_set_flag(Term tflag, Term t2):

1. Term Yap_UnknownFlag(Term mod):

1. Term getYapFlag(Term tflag):

1. static Int source(USES_REGS1):

1. static Int no_source(USES_REGS1):

1. static Int source_mode(USES_REGS1): : "source_mode(- O,+ N" )

@class source_mode_2

The state of source mode can either be on or off. When the source mode is on, all clauses are kept both as compiled code and in a "hidden" database. O is unified with the previous state and the mode is set according to N.

1. static bool setInitialValue(bool bootstrap, flag_func f, const char s, flag_term tarr):

1. static Int do_prolog_flag_property(Term tflag, Term opts USES_REGS):

1. static Int cont_prolog_flag_property(USES_REGS1):

1. static Int prolog_flag_property(USES_REGS1):

1. static Int do_create_prolog_flag(USES_REGS1):

1. X_API bool Yap_create_prolog_flag(const char *name, bool writable, Term ttype, Term v): : Create a new global prolog flag.

• name

• whether read-only or writable

• type: boolean, integer, atom, any as a pprolog term

1. void Yap_InitFlags(bool bootstrap): : Init System Prolog flags.

This is done in two phases: early on, it takes care of the atomic flags that are required by other modules; later, it looks at flags that are structured terms

bootstrapwether this is done before stack initialization, or afterwards. Complex terms can only be built in the second step.

Var:¶

1. flag_info local_flags_setup[][]:

1. flag_info global_flags_setup[][]:

1. const param2_t prolog_flag_property_defs[][]:

Typedef:¶

1. typedef enum prolog_flag_property_enum_choices prolog_flag_property_choices_t:

Enum:¶

1. prolog_flag_property_enum_choices: