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)