Re: [Texmacs-dev] Strange bug with C++

[Joris van der Hoeven]

> > > Also, exactly where does the segfault occur?
> >
> > During the destruction of ifstream.
>
> Maybe valgrind could be of some help here. There could conceivably be
> a memory corruption bug somewhere else which causes a crash in that
> destructor but cause no problem otherwise. Yes that is improbable.

I indeed have the impression that the problem is due to
the global new and delete. With gdb, I get:

--------------------------------------------------------
address@hidden src]$ gdb texmacs.bin
GNU gdb Red Hat Linux 7.x (5.0rh-15) (MI_OUT)
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This GDB was configured as "i386-redhat-linux"...
(gdb) run
Starting program: /home/vdhoeven/texmacs/distr/bin/texmacs.bin
sh: /home/vdhoeven/.TeXmacs/system/tmp/tmp_1891031863: No such file or directory
opening /home/vdhoeven/.TeXmacs/system/tmp/tmp_1891031863
opened

Program received signal SIGSEGV, Segmentation fault.
__builtin_vec_delete (ptr=0xfffffffc) at ./Classes/Abstract/basic.cc:73
73        register size_t s= *((size_t *) ptr);
(gdb) bt
#0  __builtin_vec_delete (ptr=0xfffffffc) at ./Classes/Abstract/basic.cc:73
#1  0x08263e5b in ifstream::~ifstream (this=0xbffff400, __in_chrg=2) at 
streambuf.h:487
#2  0x0810b283 in load_string (u={rep = 0x833e1d4}, address@hidden, 
fatal=false) at ./System/Files/file.cc:162
#3  0x081bc79f in eval_system (s={rep = 0x833e244}) at 
./System/Misc/sys_utils.cc:36
#4  0x081bc8a5 in var_eval_system (s={rep = 0x833e244}) at 
./System/Misc/sys_utils.cc:44
#5  0x0814bf8f in install_texmacs () at ./System/Boot/init_texmacs.cc:75
#6  0x08223797 in main (argc=1, argv=0xbffff684) at 
./Texmacs/Texmacs/texmacs.cc:195
#7  0x401cc507 in __libc_start_main (main=0x822378c <main>, argc=1, 
ubp_av=0xbffff684, init=0x804be7c <_init>, fini=0x8266e08 <_fini>,
    rtld_fini=0x4000dc14 <_dl_fini>, stack_end=0xbffff67c) at 
../sysdeps/generic/libc-start.c:129
--------------------------------------------------------

Probably, some allocations for ifstreams are done with malloc and
the destructions with delete[]. So I think that the bug comes from g++.

I think that I once have to remove the global destructors and
let them be inherited by the classes. But let's leave this for later...