From ef290276acb80e87f9148ce34ec792a2bd301d8c Mon Sep 17 00:00:00 2001 From: Jim Blandy Date: Mon, 23 Dec 1996 04:37:03 +0000 Subject: * * 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. --- libguile/gc.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'libguile/gc.c') 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)); -- cgit v1.2.3