summaryrefslogtreecommitdiff
path: root/libguile/gc.c
diff options
context:
space:
mode:
authorJim Blandy <jimb@red-bean.com>1996-12-23 04:37:03 +0000
committerJim Blandy <jimb@red-bean.com>1996-12-23 04:37:03 +0000
commitef290276acb80e87f9148ce34ec792a2bd301d8c (patch)
tree10a0b82c084a9aa8eb6c67865d007692ccf88fc3 /libguile/gc.c
parentce2a6727dc0c04603f224bb645b63c9529d49d9c (diff)
downloadguile-ef290276acb80e87f9148ce34ec792a2bd301d8c.tar.gz
* * gc.c (scm_protect_object, scm_unprotect_object): New functions.
Their prototypes were already present in gc.h, but they weren't implemented. (scm_init_storage): Initialize scm_protects. * root.c (scm_protects): New element of scm_sys_protects.
Diffstat (limited to 'libguile/gc.c')
-rw-r--r--libguile/gc.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/libguile/gc.c b/libguile/gc.c
index cd4a249d7..9d434f33e 100644
--- a/libguile/gc.c
+++ b/libguile/gc.c
@@ -1755,6 +1755,45 @@ scm_permanent_object (obj)
}
+/* 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;
+}
+
+
int
scm_init_storage (init_heap_size)
@@ -1808,6 +1847,7 @@ 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));