From 8b9cf7dc2a7e4e1327f7c84c7b9ac013df7ed57d Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@dcc.fc.up.pt>
Date: Mon, 30 Aug 2010 22:25:56 -0500
Subject: [PATCH] YAP_SetYAP_Flag

---
 C/c_interface.c        | 25 +++++++++++++++++++++++++
 changes-6.0.html       |  1 +
 docs/yap.tex           | 21 +++++++++++++++++++--
 include/YapInterface.h |  3 +++
 include/yap_structs.h  |  8 ++++++++
 5 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/C/c_interface.c b/C/c_interface.c
index a48707cf2..b6565a6fc 100755
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -519,6 +519,7 @@ X_API int      STD_PROTO(YAP_Erase,(void *));
 X_API int      STD_PROTO(YAP_Variant,(Term, Term));
 X_API int      STD_PROTO(YAP_ExactlyEqual,(Term, Term));
 X_API Int      STD_PROTO(YAP_TermHash,(Term, Int, Int, int));
+X_API int      STD_PROTO(YAP_SetYAPFlag,(yap_flag_t, int));
 
 static int (*do_getf)(void);
 
@@ -3100,4 +3101,28 @@ YAP_SlotsToArgs(int n, Int slot)
 }
 
 
+X_API int
+YAP_SetYAPFlag(yap_flag_t flag, int val)
+{
+  switch (flag) {
+  case YAPC_ENABLE_GC:
+    if (val) {
+      Yap_PutValue(AtomGc, MkAtomTerm(AtomTrue));
+    } else {
+      Yap_PutValue(AtomGc, TermNil);
+    }
+    return TRUE;
+  case YAPC_ENABLE_AGC:
+    if (val) {
+      AGcThreshold = 10000;
+    } else {
+      AGcThreshold = 0;
+    }
+    return TRUE;
+  default:
+    return FALSE;
+  }
+}
+
+
 
diff --git a/changes-6.0.html b/changes-6.0.html
index a15408ad8..be67a39b7 100644
--- a/changes-6.0.html
+++ b/changes-6.0.html
@@ -17,6 +17,7 @@
 
 <h2>Yap-6.0.7:</h2>
 <ul>
+<li> NEW: support div/2 as per WG17. </li>
 <li> FIXED: restore from / file should just try that file. </li>
 <li> FIXED: bad things can happen to P when user code is called (obs
   from Ingo Thon). </li>
diff --git a/docs/yap.tex b/docs/yap.tex
index e638bb81a..13e4cee77 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -300,6 +300,7 @@ Subnodes of C-Interface
 * Utility Functions:: From character arrays to Lists of codes and back
 * Calling YAP From C:: From C to YAP to C to YAP 
 * Module Manipulation in C:: Create and Test Modules from within C
+* Miscellaneous C-Functions:: Other Helpful Interface Functions
 * Writing C:: Writing Predicates in C
 * Loading Objects:: Loading Object Files
 * Save&Rest:: Saving and Restoring
@@ -15232,6 +15233,7 @@ The rest of this appendix describes exhaustively how to interface C to YAP.
 * Utility Functions:: From character arrays to Lists of codes and back
 * Calling YAP From C:: From C to YAP to C to YAP 
 * Module Manipulation in C:: Create and Test Modules from within C
+* Miscellaneous C-Functions:: Other Helpful Interface Functions
 * Writing C:: Writing Predicates in C
 * Loading Objects:: Loading Object Files
 * Save&Rest:: Saving and Restoring
@@ -15901,7 +15903,7 @@ finding the first solution to the goal, but you can call
 Notice that during execution, garbage collection or stack shifting may
 have moved the terms 
 
-@node Module Manipulation in C, Writing C, Calling YAP From C, C-Interface
+@node Module Manipulation in C, Miscellaneous C-Functions, Calling YAP From C, C-Interface
 @section Module Manipulation in C
 
 YAP allows one to create a new module from C-code. To create the new
@@ -15925,7 +15927,22 @@ possible by using:
 Notice that this function returns a term, and not an atom. You can
 @code{YAP_AtomOfTerm} to extract the corresponding Prolog atom.
 
-@node Writing C, Loading Objects, Module Manipulation in C, C-Interface
+@node Miscellaneous C-Functions, Writing C, Module Manipulation in C, C-Interface
+@section Miscellaneous C Functions
+
+@table @code
+@item  @code{int} YAP_SetYAPFlag(@code{yap_flag_t flag, int value})
+@findex YAP_SetYAPFlag (C-Interface function)
+
+This function allows setting some YAP flags from @code{C} .Currently,
+only two boolean flags are accepted: @code{YAPC_ENABLE_GC} and
+@code{YAPC_ENABLE_AGC}.  The first enables/disables the standard garbage
+collector, the second does the same for the atom garbage collector.`
+
+@end table
+
+
+@node Writing C, Loading Objects, Miscellaneous C-Functions, C-Interface
 @section Writing predicates in C
 
 We will distinguish two kinds of predicates:
diff --git a/include/YapInterface.h b/include/YapInterface.h
index 163b179c6..f74dc11bc 100755
--- a/include/YapInterface.h
+++ b/include/YapInterface.h
@@ -510,6 +510,9 @@ extern X_API int        PROTO(YAP_Variant,(YAP_Term,YAP_Term));
 extern X_API int        PROTO(YAP_ExactlyEqual,(YAP_Term,YAP_Term));
 extern X_API YAP_Int    PROTO(YAP_TermHash,(YAP_Term, YAP_Int, YAP_Int, int));
 
+/*  stack expansion control */
+extern X_API int        PROTO(YAP_SetYAPFlag,(yap_flag_t,int));
+
 #define YAP_InitCPred(N,A,F)  YAP_UserCPredicate(N,F,A)
 
 __END_DECLS
diff --git a/include/yap_structs.h b/include/yap_structs.h
index d2e5faf70..8af71228b 100755
--- a/include/yap_structs.h
+++ b/include/yap_structs.h
@@ -187,3 +187,11 @@ typedef enum
     YAPC_COMPILE_ALL          /* compile all predicates */
   } yapc_exec_mode;
 
+/********* YAP C-Flags ***********************/
+
+typedef enum
+  {
+    YAPC_ENABLE_GC,                 /* enable or disable garbage collection */
+    YAPC_ENABLE_AGC                 /* enable or disable atom garbage collection */
+  } yap_flag_t;
+