}
+/* Protect OBJ from the garbage collector. OBJ will not be freed,
+ even if all other references are dropped, until someone applies
+ scm_unprotect_object to it. This function returns OBJ.
+
+ Note that calls to scm_protect_object do not nest. You can call
+ scm_protect_object any number of times on a given object, and the
+ next call to scm_unprotect_object will unprotect it completely.
+
+ Basically, scm_protect_object and scm_unprotect_object just
+ maintain a list of references to things. Since the GC knows about
+ this list, all objects it mentions stay alive. scm_protect_object
+ adds its argument to the list; scm_unprotect_object remove its
+ argument from the list. */
+SCM
+scm_protect_object (obj)
+ SCM obj;
+{
+ /* This function really should use address hashing tables, but I
+ don't know how to use them yet. For now we just use a list. */
+ scm_protects = scm_cons (obj, scm_protects);
+
+ return obj;
+}
+
+
+/* Remove any protection for OBJ established by a prior call to
+ scm_protect_obj. This function returns OBJ.
+
+ See scm_protect_obj for more information. */
+SCM
+scm_unprotect_object (obj)
+ SCM obj;
+{
+ scm_protects = scm_delq_x (obj, scm_protects);
+
+ return obj;
+}
+
+
\f
int
scm_init_storage (init_heap_size)
scm_symhash_vars = scm_make_vector ((SCM) SCM_MAKINUM (scm_symhash_dim), SCM_EOL, SCM_UNDEFINED);
scm_stand_in_procs = SCM_EOL;
scm_permobjs = SCM_EOL;
+ scm_protects = SCM_EOL;
scm_asyncs = SCM_EOL;
scm_sysintern ("most-positive-fixnum", (SCM) SCM_MAKINUM (SCM_MOST_POSITIVE_FIXNUM));
scm_sysintern ("most-negative-fixnum", (SCM) SCM_MAKINUM (SCM_MOST_NEGATIVE_FIXNUM));
#define scm_object_whash scm_sys_protects[12]
#define scm_permobjs scm_sys_protects[13]
#define scm_asyncs scm_sys_protects[14]
+#define scm_protects scm_sys_protects[15]
#ifdef DEBUG_EXTENSIONS
-#define scm_source_whash scm_sys_protects[15]
-#define SCM_NUM_PROTECTS 16
+#define scm_source_whash scm_sys_protects[16]
+#define SCM_NUM_PROTECTS 17
#else
-#define SCM_NUM_PROTECTS 15
+#define SCM_NUM_PROTECTS 16
#endif
extern SCM scm_sys_protects[];