Hi Bryan, Thomas,

I think I have the same problem as you. My external crashes when I try to delete the object from the canvas i.e when the destructor of my external is called. The BT is

#0 0xb7db0334 in free () from /lib/tls/i686/cmov/libc.so.6 #1 0xb72858b1 in operator delete (ptr=0x0) at ../../../../src/libstdc++-v3/libsupc++/del_op.cc:49 #2 0xb72da0d1 in Mixer::~Mixer () from /usr/lib/libsndobj.so.2 #3 0xb733383b in resoncomb::FreeObjs () from /usr/lib/pd/extra/resoncomb~.pd_linux #4 0xb733f4af in flext_sndobj::ClearObjs () from /usr/lib/pd/extra/resoncomb~.pd_linux #5 0xb733f5e8 in flext_sndobj::Exit () from /usr/lib/pd/extra/resoncomb~.pd_linux #6 0xb733549f in flext_obj_single::obj_free () from /usr/lib/pd/extra/resoncomb~.pd_linux

I tried adding '#define FLEXT_USE_CMEM' to the top of flext.h. I rebuilt flext and installed it. I also added the define to the top of my own external and rebuilt it. No joy ;( Firstly is this/are these the correct place(s) to define FLEXT_USE_CMEM ?

Thomas while looking over the Flext docs I came across this :

"Some few external libraries have troubles with flext's global new and delete overloadings. In these cases one can switch back to the C library memory operators by defining the FLEXT_NOGLOBALNEW macro before inclusion of the flext.h header file (e.g. as a -D compiler option)"

Again where should this FLEXT_NOGLOBALNEW be defined? in the package.txt ? (Sorry I am by no means experienced with this native stuff).

Would this bug be related to the problem I am experiencing. The exception is thrown on a delete of SndObj pointer. I have already talked to Victor and he has never seen anything like this before.

So frustrating, I have finished my first PD external (Multi stereo comb filter) and I want to release it properly but I can't with this bug in it !!!

Conor

Thomas Grill wrote:

Hi Bryan, i think it would be a good idea to define FLEXT_USE_CMEM in the flext
build system by default. Currently pd doesn't use anything different than C memory allocation
(in getbytes, freebytes) so there's no real reason to not to. Concerning your fluid problems i can't really help, since i don't use
it, but i'm sure there are some experts who can.

all the best, Thomas

Am 28.01.2007 um 17:17 schrieb Bryan Jurish:

morning all,

I've been chasing a bug for several weeks now that I just can't
seem to get my head around: symptoms are segfaults and complete crashes in pd (v0.40-2 vanilla) on linux/x86 [debian unstable, gcc 4.1.2]. gdb backtraces are available, and I've just recompiled using identical CFLAGS everywhere (-O3 -march=pentium-m -msse -msse2 -mfpmath=sse -ffast-math -funroll-loops), since I had feared that -malign-double might have been biting me, but this doesn't appear to have been the
case...

Buglet the First (solved, kinda)

• description: [pool] and [readanysf~] don't play nicely together
• symptom: the (infamous) libc message on stderr when closing a patch: *** glibc detected *** free(): invalid pointer: 0x0823e46c ***
  • apparently caused by some goofiness with the flext delete()

operator (backtraces etc. available)

• solution (I think, thanks to the list archives):
  • compile both flext and readanysf~ with -DFLEXT_USE_CMEM
  • readanysf~ really seems to need FLEXT_USE_CMEM flext-globally

(I can provide a pretty complete and systematic list of the configurations
I've tried: it's possible to compile and run successfully without FLEXT_USE_CMEM, but things break more or less randomly at runtime
then: particularly, the "stop" message to readanysf~ segfaults pd)

• solution (I think, thanks to the list archives):
  • this seems to work for [pool] and [readanysf~], but...

Buglet the Second (please assist!)

• description: [fluid~] in abstractions crashes pd
  • having compiled flext with -DFLEXT_USE_CMEM, loading any

abstraction containing a [fluid~] object causes pd to segfault (see below)

• bug occurs even without any other externals loaded

• oddly, I *can* create [fluid~]s by hand, (but not load them in an abstraction, which makes the object pretty useless, im(ns)ho)

• any ideas why fluid_init() is trying to initialize this==NULL ?

  • this appears to be FLEXT_USE_CMEM related, since I didn't get these symptoms without FLEXT_USE_CMEM in flext itself

• I can't just -UFLEXT_USE_CMEM for fluid~, because: (a) that would break readanysf~ if I did it flext-globally, and (b) if I undefine FLEXT_USE_CMEM only for fluid~, I get undefined linker symbols at runtime:

  /usr/local/lib/pd/extra/fluid~.pd_linux: \
  /usr/local/lib/pd/extra/fluid~.pd_linux: undefined symbol: \
    _ZN19flext_root_single_ddlEPv \
  

  fluid~: can't load library

• would it help to fork the flext build procedure (again!), basically adding another library suffix for FLEXT_USE_CMEM, since its effects appear not to be restricted to the headers?

  • if the suffix were, say, 'c', where we now have: libflext-pd((_d)?.so|_[st]d?.a) we would get: libflext-pd((_c?d?).so|_[st]c?d?.a)
  • i know this is ugly, and I'm not even sure it would work, but I'm at my wits' end here... I hope somebody can shed some light on this for me...

Program received signal SIGSEGV, Segmentation fault. [Switching to Thread -1210693952 (LWP 24068)] 0xb7dcb589 in free () from /lib/tls/i686/cmov/libc.so.6 (gdb) backtrace #0 0xb7dcb589 in free () from /lib/tls/i686/cmov/libc.so.6 #1 0xb7d1e639 in delete_fluid_synth () from /usr/lib/ libfluidsynth.so.1 #2 0x08237bd0 in ?? () #3 0x0811ace0 in mstack.5434 () #4 0xbfd76828 in ?? () #5 0xb7d47366 in fluid::fluid_init (this=0x0, argc=-1210746848, argv=0xb7caf730) at fluid/main.cpp:251 Previous frame inner to this frame (corrupt stack?)

marmosets, Bryan