It seems that's not the problem. Refcount is 0, yet the object is kept alive.
Running the modified script below, I get the following:
[BEGIN OUTPUT]
p is #<point* #2 0x12309a0> release-point called on serial 3 found in object table as: #<void* #3 0x12309a0>
*** after GC: foreign serial is 3, corresponding to #<void* #3 0x12309a0>, a mem-allocated still object with reference count == 0 Bye.
[END OUTPUT]
;--------------------------------------------------------------------------------------
(c-declare "struct { int x; int y; } point;")
(define no-err ((c-lambda () scheme-object "___result = ___FIX(___NO_ERR);")))
(define ptr-serial #f)
(c-define (release-point ptr) ((pointer void)) scheme-object "scm_release_point" "" (set! ptr-serial (object->serial-number ptr)) (println "release-point called on serial " ptr-serial) (println "found in object table as: " (table-ref ##serial-number-to-object-table ptr-serial 'not-there)) ((c-lambda ((pointer void)) void "___release_rc") ptr) no-err)
(c-define-type point (type "point" (point*) "scm_release_point"))
(define p ((c-lambda () point "___result_voidstar = ___EXT(___alloc_rc)(sizeof(point));")))
(println "p is " p)
(set! p #f)
(##gc)
(newline) (println "*** after GC:") (print "foreign serial is " ptr-serial) (print ", corresponding to " (table-ref ##serial-number-to-object-table ptr-serial 'not-there))
(print ", a " (if ((c-lambda (scheme-object) bool "___result = ___MEM_ALLOCATED(___arg1);") (table-ref ##serial-number-to-object-table ptr-serial 'not-there)) "" "not") " mem-allocated")
(print " " ((c-lambda (scheme-object) char-string "___result = ___HD_TYP(___BODY(___arg1)[-1]) == ___STILL ? "still" : "something else";") (table-ref ##serial-number-to-object-table ptr-serial 'not-there)))
(println " object with reference count == " ((c-lambda (scheme-object) int "___result = ___UNTAG(___arg1)[___BODY_OFS - 6 + 1];") (table-ref ##serial-number-to-object-table ptr-serial 'not-there)))
(println "Bye.")
On Mon, Dec 30, 2013 at 10:09 AM, Mikael mikael.rcv@gmail.com wrote:
Refcount is 1 by default so you need to decrease it for it to GFC?
Allocate a zillion points and check the two respective ways.
2013/12/29 Estevo euccastro@gmail.com
Here's a more realistic version of what I was trying to do:
(c-declare "struct { int x; int y; } point;")
(define no-err ((c-lambda () scheme-object "___result = ___FIX(___NO_ERR);")))
(c-define (release-point ptr) ((pointer void)) scheme-object "scm_release_point" "" (println "release-point called") ((c-lambda ((pointer void)) void "___release_rc") ptr) no-err)
(c-define-type point (pointer "point" (point*) "scm_release_point"))
(define p ((c-lambda () point "___result_voidstar = ___EXT(___alloc_rc)(sizeof(point));")))
(println "p is " p) (set! p #f)
(##gc)
(println "Bye.")
valgrind's complaint is different in this one. What is leaked here (again, unless valgrind is giving me a false positive) seems to be the Scheme representation of `ptr`:
==9631== Memcheck, a memory error detector ==9631== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al. ==9631== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==9631== Command: ./test-c-define ==9631== p is #<point* #2 0x5c04620> release-point called Bye. ==9631== ==9631== HEAP SUMMARY: ==9631== in use at exit: 158 bytes in 2 blocks ==9631== total heap usage: 154 allocs, 152 frees, 4,247,245 bytes allocated ==9631== ==9631== 158 (87 direct, 71 indirect) bytes in 1 blocks are definitely lost in loss record 2 of 2 ==9631== at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==9631== by 0x4C7DC6: ___alloc_mem (os_base.c:185) ==9631== by 0x4B6905: alloc_mem_aligned (mem.c:452) ==9631== by 0x4B77A7: alloc_scmobj_still (mem.c:1245) ==9631== by 0x4B78B1: ___alloc_scmobj (mem.c:1285) ==9631== by 0x4C3DEE: ___POINTER_to_SCMOBJ (c_intf.c:5154) ==9631== by 0x4B1C88: scm_release_point (test-c-define.c:665) ==9631== by 0x4C1027: ___release_foreign (c_intf.c:1713) ==9631== by 0x4BAEA4: free_unmarked_still_objs (mem.c:3271) ==9631== by 0x4BD472: ___garbage_collect (mem.c:4698) ==9631== by 0x4E4357: ___H__20___kernel (_kernel.c:9170) ==9631== by 0x4B49B2: trampoline (setup.c:1618) ==9631== ==9631== LEAK SUMMARY: ==9631== definitely lost: 87 bytes in 1 blocks ==9631== indirectly lost: 71 bytes in 1 blocks ==9631== possibly lost: 0 bytes in 0 blocks ==9631== still reachable: 0 bytes in 0 blocks ==9631== suppressed: 0 bytes in 0 blocks ==9631== ==9631== For counts of detected and suppressed errors, rerun with: -v ==9631== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)
On Thu, Dec 26, 2013 at 11:23 PM, Estevo euccastro@gmail.com wrote:
Valgrind reports Gambit is leaking a "sfun stack marker" if I call, from a foreign release function, another function defined with `c-define`. The code below is about the most innocent looking thing I could come up with.
Doesn't Gambit like c-define functions called within release functions, or is Valgrind giving me a false positive here (as it is wont to do quite often.)
; ~/gambit-dbg/bin/gsc -exe -cc-options -g test-c-define.scm && valgrind --leak-check=full ./test-c-define
(c-declare #<<c-declare-end
typedef struct { int x; int y; } point;
void scm_release_point(unsigned long);
___SCMOBJ c_release_point(void *ptr) { scm_release_point((unsigned long)ptr); ___EXT(___release_rc)(ptr); return ___FIX(___NO_ERR); }
c-declare-end )
(c-define (release-point ptr) (unsigned-long) void "scm_release_point" "" (println "release-point called"))
(c-define-type point (pointer "point" (point*) "c_release_point"))
(define p ((c-lambda () point "___result_voidstar = ___EXT(___alloc_rc)(sizeof(point));")))
(println "p is " p) (set! p #f)
(##gc) ; for good measure... (##gc) (##gc)
(println "Bye.")
valgrind --leak-check=full ./test-c-define ==16301== Memcheck, a memory error detector ==16301== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al. ==16301== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==16301== Command: ./test-c-define ==16301== p is #<point* #2 0x5c04640> release-point called Bye. ==16301== ==16301== HEAP SUMMARY: ==16301== in use at exit: 71 bytes in 1 blocks ==16301== total heap usage: 153 allocs, 152 frees, 4,247,198 bytes allocated ==16301== ==16301== 71 bytes in 1 blocks are definitely lost in loss record 1 of 1 ==16301== at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==16301== by 0x4C922E: ___alloc_mem (os_base.c:185) ==16301== by 0x4B7DB5: alloc_mem_aligned (mem.c:452) ==16301== by 0x4B8C57: alloc_scmobj_still (mem.c:1245) ==16301== by 0x4B8D61: ___alloc_scmobj (mem.c:1285) ==16301== by 0x4B8E44: ___make_vector (mem.c:1362) ==16301== by 0x4C677B: ___make_sfun_stack_marker (c_intf.c:6452) ==16301== by 0x4B359E: scm_release_point (test-c-define.c:139) ==16301== by 0x4B354B: c_release_point (test-c-define.c:130) ==16301== by 0x4C24D7: ___release_foreign (c_intf.c:1713) ==16301== by 0x4BC354: free_unmarked_still_objs (mem.c:3271) ==16301== by 0x4BE922: ___garbage_collect (mem.c:4698) ==16301== ==16301== LEAK SUMMARY: ==16301== definitely lost: 71 bytes in 1 blocks ==16301== indirectly lost: 0 bytes in 0 blocks ==16301== possibly lost: 0 bytes in 0 blocks ==16301== still reachable: 0 bytes in 0 blocks ==16301== suppressed: 0 bytes in 0 blocks ==16301== ==16301== For counts of detected and suppressed errors, rerun with: -v ==16301== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)
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