popen support

C/c_interface.c

@@ -2119,7 +2119,7 @@ X_API int YAP_InitConsult(int mode, const char *fname, char **full, int *osnop)
     }
   }
   bool consulted = (mode == YAP_CONSULT_MODE);
-  sno = Yap_OpenStream(fl, "r", MkAtomTerm(Yap_LookupAtom(fl)), LOCAL_encoding);
+  sno = Yap_OpenStream(MkStringTerm(fl), "r", MkAtomTerm(Yap_LookupAtom(fl)), LOCAL_encoding);
     if (sno < 0 ||
 	!Yap_ChDir(dirname((char *)fl))) {
       pop_text_stack(lvl);

H/ATOMS

@@ -290,15 +290,15 @@ A	OutOfStackError		N	"out_of_stack_error"
 A	OutOfTrailError		N	"out_of_trail_error"
 A	Output			N	"output"
 A	Parameter		N	"parameter"
-A	PrologCommonsDir	N	"prolog_commons_directory"
 A	Past			N	"past"
 A	PastEndOfStream		N	"past_end_of_stream"
 A	PermissionError		N	"permission_error"
 A	Pi			N	"pi"
 A	Pipe			N	"pipe"
-A   Priority		N   "priority"
+A	Priority		N   "priority"
 A	Plus			N	"+"
 A	Pointer			N	"pointer"
+A	Popen			N	"popen"
 A	Portray			F	"portray"
 A	PredicateIndicator	N	"predicate_indicator"
 A	Primitive		N	"primitive"
@@ -307,6 +307,7 @@ A	PrivateProcedure	N	"private_procedure"
 A	Procedure		N	"procedure"
 A	Profile			F	"$profile"
 A	Prolog			N	"prolog"
+A	PrologCommonsDir	N	"prolog_commons_directory"
 A	ProtectStack	F	"$protect_stack"
 A	Qly			    N	"qly"
 A	Query			N	"?-"
@@ -558,6 +559,7 @@ F	Or			Semic		2
 F   Output      Output      1
 F	PermissionError		PermissionError	3
 F	Plus			Plus		2
+F	Popen			Popen		1
 F	Portray			Portray		1
 F	PrintMessage		PrintMessage	2
 F   Procedure       Procedure       5

H/generated/iatoms.h

@@ -285,7 +285,6 @@
   AtomOutOfTrailError = Yap_LookupAtom("out_of_trail_error"); TermOutOfTrailError = MkAtomTerm(AtomOutOfTrailError);
   AtomOutput = Yap_LookupAtom("output"); TermOutput = MkAtomTerm(AtomOutput);
   AtomParameter = Yap_LookupAtom("parameter"); TermParameter = MkAtomTerm(AtomParameter);
-  AtomPrologCommonsDir = Yap_LookupAtom("prolog_commons_directory"); TermPrologCommonsDir = MkAtomTerm(AtomPrologCommonsDir);
   AtomPast = Yap_LookupAtom("past"); TermPast = MkAtomTerm(AtomPast);
   AtomPastEndOfStream = Yap_LookupAtom("past_end_of_stream"); TermPastEndOfStream = MkAtomTerm(AtomPastEndOfStream);
   AtomPermissionError = Yap_LookupAtom("permission_error"); TermPermissionError = MkAtomTerm(AtomPermissionError);
@@ -294,6 +293,7 @@
   AtomPriority = Yap_LookupAtom("priority"); TermPriority = MkAtomTerm(AtomPriority);
   AtomPlus = Yap_LookupAtom("+"); TermPlus = MkAtomTerm(AtomPlus);
   AtomPointer = Yap_LookupAtom("pointer"); TermPointer = MkAtomTerm(AtomPointer);
+  AtomPopen = Yap_LookupAtom("popen"); TermPopen = MkAtomTerm(AtomPopen);
   AtomPortray = Yap_FullLookupAtom("portray"); TermPortray = MkAtomTerm(AtomPortray);
   AtomPredicateIndicator = Yap_LookupAtom("predicate_indicator"); TermPredicateIndicator = MkAtomTerm(AtomPredicateIndicator);
   AtomPrimitive = Yap_LookupAtom("primitive"); TermPrimitive = MkAtomTerm(AtomPrimitive);
@@ -302,6 +302,7 @@
   AtomProcedure = Yap_LookupAtom("procedure"); TermProcedure = MkAtomTerm(AtomProcedure);
   AtomProfile = Yap_FullLookupAtom("$profile"); TermProfile = MkAtomTerm(AtomProfile);
   AtomProlog = Yap_LookupAtom("prolog"); TermProlog = MkAtomTerm(AtomProlog);
+  AtomPrologCommonsDir = Yap_LookupAtom("prolog_commons_directory"); TermPrologCommonsDir = MkAtomTerm(AtomPrologCommonsDir);
   AtomProtectStack = Yap_FullLookupAtom("$protect_stack"); TermProtectStack = MkAtomTerm(AtomProtectStack);
   AtomQly = Yap_LookupAtom("qly"); TermQly = MkAtomTerm(AtomQly);
   AtomQuery = Yap_LookupAtom("?-"); TermQuery = MkAtomTerm(AtomQuery);
@@ -553,6 +554,7 @@
   FunctorOutput = Yap_MkFunctor(AtomOutput,1);
   FunctorPermissionError = Yap_MkFunctor(AtomPermissionError,3);
   FunctorPlus = Yap_MkFunctor(AtomPlus,2);
+  FunctorPopen = Yap_MkFunctor(AtomPopen,1);
   FunctorPortray = Yap_MkFunctor(AtomPortray,1);
   FunctorPrintMessage = Yap_MkFunctor(AtomPrintMessage,2);
   FunctorProcedure = Yap_MkFunctor(AtomProcedure,5);

H/generated/ratoms.h

@@ -285,7 +285,6 @@
   AtomOutOfTrailError = AtomAdjust(AtomOutOfTrailError); TermOutOfTrailError = MkAtomTerm(AtomOutOfTrailError);
   AtomOutput = AtomAdjust(AtomOutput); TermOutput = MkAtomTerm(AtomOutput);
   AtomParameter = AtomAdjust(AtomParameter); TermParameter = MkAtomTerm(AtomParameter);
-  AtomPrologCommonsDir = AtomAdjust(AtomPrologCommonsDir); TermPrologCommonsDir = MkAtomTerm(AtomPrologCommonsDir);
   AtomPast = AtomAdjust(AtomPast); TermPast = MkAtomTerm(AtomPast);
   AtomPastEndOfStream = AtomAdjust(AtomPastEndOfStream); TermPastEndOfStream = MkAtomTerm(AtomPastEndOfStream);
   AtomPermissionError = AtomAdjust(AtomPermissionError); TermPermissionError = MkAtomTerm(AtomPermissionError);
@@ -294,6 +293,7 @@
   AtomPriority = AtomAdjust(AtomPriority); TermPriority = MkAtomTerm(AtomPriority);
   AtomPlus = AtomAdjust(AtomPlus); TermPlus = MkAtomTerm(AtomPlus);
   AtomPointer = AtomAdjust(AtomPointer); TermPointer = MkAtomTerm(AtomPointer);
+  AtomPopen = AtomAdjust(AtomPopen); TermPopen = MkAtomTerm(AtomPopen);
   AtomPortray = AtomAdjust(AtomPortray); TermPortray = MkAtomTerm(AtomPortray);
   AtomPredicateIndicator = AtomAdjust(AtomPredicateIndicator); TermPredicateIndicator = MkAtomTerm(AtomPredicateIndicator);
   AtomPrimitive = AtomAdjust(AtomPrimitive); TermPrimitive = MkAtomTerm(AtomPrimitive);
@@ -302,6 +302,7 @@
   AtomProcedure = AtomAdjust(AtomProcedure); TermProcedure = MkAtomTerm(AtomProcedure);
   AtomProfile = AtomAdjust(AtomProfile); TermProfile = MkAtomTerm(AtomProfile);
   AtomProlog = AtomAdjust(AtomProlog); TermProlog = MkAtomTerm(AtomProlog);
+  AtomPrologCommonsDir = AtomAdjust(AtomPrologCommonsDir); TermPrologCommonsDir = MkAtomTerm(AtomPrologCommonsDir);
   AtomProtectStack = AtomAdjust(AtomProtectStack); TermProtectStack = MkAtomTerm(AtomProtectStack);
   AtomQly = AtomAdjust(AtomQly); TermQly = MkAtomTerm(AtomQly);
   AtomQuery = AtomAdjust(AtomQuery); TermQuery = MkAtomTerm(AtomQuery);
@@ -553,6 +554,7 @@
   FunctorOutput = FuncAdjust(FunctorOutput);
   FunctorPermissionError = FuncAdjust(FunctorPermissionError);
   FunctorPlus = FuncAdjust(FunctorPlus);
+  FunctorPopen = FuncAdjust(FunctorPopen);
   FunctorPortray = FuncAdjust(FunctorPortray);
   FunctorPrintMessage = FuncAdjust(FunctorPrintMessage);
   FunctorProcedure = FuncAdjust(FunctorProcedure);

H/generated/tatoms.h

@@ -285,7 +285,6 @@ X_API EXTERNAL Atom AtomOutOfStackError; X_API EXTERNAL Term TermOutOfStackError
 X_API EXTERNAL Atom AtomOutOfTrailError; X_API EXTERNAL Term TermOutOfTrailError;
 X_API EXTERNAL Atom AtomOutput; X_API EXTERNAL Term TermOutput;
 X_API EXTERNAL Atom AtomParameter; X_API EXTERNAL Term TermParameter;
-X_API EXTERNAL Atom AtomPrologCommonsDir; X_API EXTERNAL Term TermPrologCommonsDir;
 X_API EXTERNAL Atom AtomPast; X_API EXTERNAL Term TermPast;
 X_API EXTERNAL Atom AtomPastEndOfStream; X_API EXTERNAL Term TermPastEndOfStream;
 X_API EXTERNAL Atom AtomPermissionError; X_API EXTERNAL Term TermPermissionError;
@@ -294,6 +293,7 @@ X_API EXTERNAL Atom AtomPipe; X_API EXTERNAL Term TermPipe;
 X_API EXTERNAL Atom AtomPriority; X_API EXTERNAL Term TermPriority;
 X_API EXTERNAL Atom AtomPlus; X_API EXTERNAL Term TermPlus;
 X_API EXTERNAL Atom AtomPointer; X_API EXTERNAL Term TermPointer;
+X_API EXTERNAL Atom AtomPopen; X_API EXTERNAL Term TermPopen;
 X_API EXTERNAL Atom AtomPortray; X_API EXTERNAL Term TermPortray;
 X_API EXTERNAL Atom AtomPredicateIndicator; X_API EXTERNAL Term TermPredicateIndicator;
 X_API EXTERNAL Atom AtomPrimitive; X_API EXTERNAL Term TermPrimitive;
@@ -302,6 +302,7 @@ X_API EXTERNAL Atom AtomPrivateProcedure; X_API EXTERNAL Term TermPrivateProcedu
 X_API EXTERNAL Atom AtomProcedure; X_API EXTERNAL Term TermProcedure;
 X_API EXTERNAL Atom AtomProfile; X_API EXTERNAL Term TermProfile;
 X_API EXTERNAL Atom AtomProlog; X_API EXTERNAL Term TermProlog;
+X_API EXTERNAL Atom AtomPrologCommonsDir; X_API EXTERNAL Term TermPrologCommonsDir;
 X_API EXTERNAL Atom AtomProtectStack; X_API EXTERNAL Term TermProtectStack;
 X_API EXTERNAL Atom AtomQly; X_API EXTERNAL Term TermQly;
 X_API EXTERNAL Atom AtomQuery; X_API EXTERNAL Term TermQuery;
@@ -662,6 +663,8 @@ X_API EXTERNAL  Functor FunctorPermissionError;
 
 X_API EXTERNAL  Functor FunctorPlus;
 
+X_API EXTERNAL  Functor FunctorPopen;
+
 X_API EXTERNAL  Functor FunctorPortray;
 
 X_API EXTERNAL  Functor FunctorPrintMessage;

library/lineutils.yap

@@ -64,21 +64,6 @@ available by loading the
 :- use_module(library(readutil),
 	      [read_line_to_codes/2]).
 
-re_open(S, Mode, S) :-
-	is_stream(S),
-	!,
-	current_stream(_, Mode, S).
-re_open(F, Mode, S) :-
-	open(F, Mode, S).
-
-re_open(S, Mode, S, Props) :-
-	is_stream(S),
-	!,
-	current_stream(_, Mode, S),
-	maplist( set_stream(S), Props).
-re_open(F, Mode, S, Props) :-
-	open(F, Mode, S, Props).
-
 /**
  @pred search_for(+ _Char_,+ _Line_)
   Search for a character  _Char_ in the list of codes  _Line_.
@@ -469,8 +454,8 @@ process(StreamInp, Command) :-
   the output stream is accessible through `filter_output`.
 */
 file_filter(Inp, Out, Command) :-
-	re_open(Inp, read, StreamInp, [alias(filter_input)]),
+	open(Inp, read, StreamInp, [alias(filter_input)]),
-	re_open(Out, write, StreamOut),
+	open(Out, write, StreamOut),
 	filter(StreamInp, StreamOut, Command),
 	close(StreamInp),
 	close(StreamOut).
@@ -482,8 +467,8 @@ Same as file_filter/3, but before starting the filter execute
  _Arguments_.
 */
 file_filter_with_initialization(Inp, Out, Command, FormatString, Parameters) :-
-	re_open(Inp, read, StreamInp, [alias(filter_input)]),
+	open(Inp, read, StreamInp, [alias(filter_input)]),
-	re_open(Out, write, StreamOut, [alias(filter_output)]),
+	open(Out, write, StreamOut, [alias(filter_output)]),
 	format(StreamOut, FormatString, Parameters),
 	filter(StreamInp, StreamOut, Command),
 	close(StreamInp),
@@ -498,8 +483,8 @@ _StartGoal_,  and call _ENdGoal_ as an epilog.
 The input stream are always accessible through `filter_output` and `filter_input`.
 */
 file_filter_with_start_end(Inp, Out, Command, StartGoal, EndGoal) :-
-	re_open(Inp, read, StreamInp, [alias(filter_input)]),
+	open(Inp, read, StreamInp, [alias(filter_input)]),
-	re_open(Out, write, StreamOut, [alias(filter_output)]),
+	open(Out, write, StreamOut, [alias(filter_output)]),
 	call( StartGoal, StreamInp, StreamOut ),
 	filter(StreamInp, StreamOut, Command),
 	call( EndGoal, StreamInp, StreamOut ),
@@ -525,7 +510,7 @@ file_filter_with_start_end(Inp, Out, Command, StartGoal, EndGoal) :-
 file_select(Inp, Command) :-
 	( retract(alias(F)) -> true ; F = '' ),
 	atom_concat(filter_input, F, Alias),
-        re_open(Inp, read, StreamInp, [Alias]),
+        open(Inp, read, StreamInp, [Alias]),
 	atom_concat('_', F, NF),
 	assert( alias(NF) ),
 	repeat,

library/system.yap

@@ -2,9 +2,9 @@
 *									 *
 *	 YAP Prolog 							 *
 *									 *
-  *	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
+ *	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
 *									 *
-  * Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
+ * Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
 *									 *
 **************************************************************************
 *									 *
@@ -74,44 +74,7 @@ are available through the `use_module(library(system))` command.
 
 */
 
-/**
 
- @pred datime(datime(- _Year_, - _Month_, - _DayOfTheMonth_, - _Hour_, - _Minute_, - _Second_)
-
-The datime/1 procedure returns the current date and time, with
-information on  _Year_,  _Month_,  _DayOfTheMonth_,
- _Hour_,  _Minute_, and  _Second_. The  _Hour_ is returned
-on local time. This function uses the WIN32
-`GetLocalTime` function or the Unix `localtime` function.
-
-~~~~~
-   ?- datime(X).
-
-X = datime(2001,5,28,15,29,46) ?
-~~~~~
-
-
-*/
-
-
-/** @pred  environ(+ _E_,- _S_)
-
-
-
-
-
-  Given an environment variable  _E_ this predicate unifies the second argument  _S_ with its value.
-
-
-*/
-/** @pred  system(+ _S_)
-
-
-Passes command  _S_ to the Bourne shell (on UNIX environments) or the
-current command interpreter in WIN32 environments.
-
-
-*/
 /** @pred  working_directory(- _CurDir_,? _NextDir_)
 
 
@@ -176,27 +139,6 @@ X = 'C:\\cygwin\\home\\administrator' ?
 ~~~~~
 
 
-*/
-/** @pred exec(+ _Command_, _StandardStreams_,- _PID_)
-
-
-Execute command  _Command_ with its standard streams connected to
-the list [_InputStream_,  _OutputStream_, _ErrorStream_]. The
-process that executes the command is returned as  _PID_. The
-command is executed by the default shell `bin/sh -c` in Unix.
-
-The following example demonstrates the use of exec/3 to send a
-command and process its output:
-
-~~~~~
-exec(ls,[std,pipe(S),null],P),repeat, get0(S,C), (C = -1, close(S) ! ; put(C)).
-~~~~~
-
-The streams may be one of standard stream, `std`, null stream,
-`null`, or `pipe(S)`, where  _S_ is a pipe stream. Note
-that it is up to the user to close the pipe.
-
-
 */
 /** @pred file_exists(+ _File_)
 
@@ -289,37 +231,7 @@ process. An interface to the <tt>getpid</tt> function.
 
 
 */
-/** @pred popen(+ _Command_, + _TYPE_, - _Stream_)
 
-
-Interface to the <tt>popen</tt> function. It opens a process by creating a
-pipe, forking and invoking  _Command_ on the current shell. Since a
-pipe is by definition unidirectional the  _Type_ argument may be
-`read` or `write`, not both. The stream should be closed
-using close/1, there is no need for a special `pclose`
-command.
-
-The following example demonstrates the use of popen/3 to process
-the output of a command, as exec/3 would do:
-
-~~~~~{.prolog}
-   ?- popen(ls,read,X),repeat, get0(X,C), (C = -1, ! ; put(C)).
-
-X = 'C:\\cygwin\\home\\administrator' ?
-~~~~~
-
-The WIN32 implementation of popen/3 relies on exec/3.
-
-
-*/
-/** @pred rename_file(+ _OldFile_,+ _NewFile_)
-
-
-Create file  _OldFile_ to  _NewFile_. This predicate uses the
-`C` built-in function `rename`.
-
-
-*/
 /** @pred read_link(+ SymbolicLink, -Link, -NewPath)
 
 
@@ -423,6 +335,24 @@ also `absolute_file_name/2` and chdir/1.
 
 % time builtins
 
+/**
+
+ @pred datime(datime(- _Year_, - _Month_, - _DayOfTheMonth_, - _Hour_, - _Minute_, - _Second_)
+
+The datime/1 procedure returns the current date and time, with
+information on  _Year_,  _Month_,  _DayOfTheMonth_,
+ _Hour_,  _Minute_, and  _Second_. The  _Hour_ is returned
+on local time. This function uses the WIN32
+`GetLocalTime` function or the Unix `localtime` function.
+
+~~~~~
+   ?- datime(X).
+
+X = datime(2001,5,28,15,29,46) ?
+~~~~~
+
+
+*/
 datime(X) :-
 	datime(X, Error),
 	handle_system_internal(Error, off, datime(X)).
@@ -567,10 +497,14 @@ file_property(File, Type, Size, Date, Permissions, LinkName) :-
 	handle_system_internal(Error, off, file_property(File)).
 
 
-%
+/** @pred  environ(+E, -S)
-% environment manipulation.
-%
 
+  Given an environment variable _E_ this predicate unifies the second
+  argument _S_ with its value. _E_ may be bound to an atom, or just be
+  unbound. In the latter case environ/2 will enumerate over all
+  environment variables.
+
+*/
 environ(Na,Val) :- var(Na), !,
 	environ_enum(0,I),
 	( p_environ(I,S) -> environ_split(S,SNa,SVal) ; !, fail ),
@@ -597,9 +531,33 @@ environ_split([61|SVal], [], SVal) :- !.
 environ_split([C|S],[C|SNa],SVal) :-
 	environ_split(S,SNa,SVal).
 
-%
+/** @pred exec(+ _Command_, _StandardStreams_,- _PID_)
-% process execution
+ *
-%
+ *
+ * 
+ * Execute command _Command_ with its standard streams connected to the
+ * list [_InputStream_, _OutputStream_, _ErrorStream_]. A numeric
+ * identifier to the process that executes the command is returned as
+ * _PID_. The command is executed by the default shell `bin/sh -c` in
+ * Unix.
+ * 
+ * The following example demonstrates the use of exec/3 to send a
+ * command and process its output:
+ * 
+ * ~~~~~
+  go :-
+     exec(ls,[std,pipe(S),null],P),
+     repeat,
+     get0(S,C),
+     (C = -1, close(S) ! ; put(C)).
+~~~~~
+ * 
+ * The streams may be one of standard stream, `std`, null stream,
+ * `null`, or `pipe(S)`, where  _S_ is a pipe stream. Note
+ * that it is up to the user to close the pipe.
+ * 
+ * 
+*/
 exec(Command, [StdIn, StdOut, StdErr], PID) :-
 	G = exec(Command, [StdIn, StdOut, StdErr], PID),
 	check_command_with_default_shell(Command, TrueCommand, G),
@@ -652,8 +610,32 @@ close_temp_streams([S|Ss]) :-
 	close(S),
 	close_temp_streams(Ss).
 
-popen(Command, Mode, Stream) :-
+/** @pred popen(+ _Command_, + _TYPE_, - _Stream_)
-	open(pipe(Command), Mode, Stream).
+
+ * Provides the functionaluty of the Unix <tt>popen</tt> function. It
+ * opens a process by creating a pipe, forking and invoking _Command_ on
+ * the child process. Since a pipe is by definition unidirectional the
+ * _Type_ argument may be `read` or `write`, not both. The stream should
+ * be closed using close/1, there is no need for a special `pclose`
+ * command.
+ * 
+ * The following example demonstrates the use of popen/3 to process the
+ * output of a command, note that popen/3 works as a simplified interface
+ * to the exec/3 command:
+ *
+~~~~~{.prolog}
+?- popen(ls,read,X),repeat, get0(X,C), (C = -1, ! ; put(C)).
+
+X = 'C:\\cygwin\\home\\administrator' ?
+~~~~~
+ * 
+ * The implementation of popen/3 relies on exec/3. 
+ *
+*/
+popen(Command, read, Stream) :-
+	exec(Command, [std,pipe(Stream),std], Stream).
+popen(Command, write, Stream) :-
+	exec(Command, [pipe(Stream),std,std], Stream).
 
 check_command_with_default_shell(Com, ComF, G) :-
 	check_command(Com, G),
@@ -811,5 +793,23 @@ read_link(P,D,F) :-
 	read_link(P, D),
 	absolute_file_name(D, [], F).
 
+/** @pred rename_file(+ _OldFile_,+ _NewFile_)
+
+
+Create file  _OldFile_ to  _NewFile_. This predicate uses the
+`C` built-in function `rename`.
+
+
+*/
+rename_file(F0, F) :-
+	rename_file(F0, F, Error),
+	handle_system_internal(Error, off, rename_file(F0, F))).
+
+/** @pred  system(+ _S_)
+
+Passes command  _S_ to the Bourne shell (on UNIX environments) or the
+current command interpreter in WIN32 environments.
+*/
+
 /** @} */
 

library/system/sys.c

@@ -729,7 +729,15 @@ static YAP_Bool execute_command(void) {
 #endif /* UNIX code */
 }
 
-/* execute a command as a detached process */
+/** @pred  system(+ _S_)
+
+Passes command  _S_ to the Bourne shell (on UNIX environments) or the
+current command interpreter in WIN32 environments.
+
+Note that it executes them command as a detached process. It requires
+`system` to be implemented by the system library.
+
+*/
 static YAP_Bool do_system(void) {
   char *command = (char *)YAP_AtomName(YAP_AtomOfTerm(YAP_ARG1));
 #if HAVE_SYSTEM

os/yapio.h

@@ -86,7 +86,7 @@ extern int Yap_PlGetWchar(void);
 extern int Yap_PlFGetchar(void);
 extern int Yap_GetCharForSIGINT(void);
 extern Int Yap_StreamToFileNo(Term);
-extern int Yap_OpenStream(const char *fname, const char* io_mode, Term user_name, encoding_t enc);
+extern int Yap_OpenStream(Term tin, const char* io_mode, Term user_name, encoding_t enc);
 extern int Yap_FileStream(FILE*, char *, Term, int, VFS_t *);
 extern char *Yap_TermToBuffer(Term t, encoding_t encoding, int flags);
 extern char *Yap_HandleToString(yhandle_t l, size_t sz, size_t *length,