Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c++ > #15451

Re: string close causes SIGSEGV

Show all headers | View raw

Lacek <mateusz.lacki@gmail.com> wrote:
> I have run into  a problem when closing a string. In particular I open
> a ofstream, I write about 40 lines of numbers. After that I close the
> stream:

> file.close();

> but that line seems to cause a SIGSEGV. THis is confirmed by a
> debugger:

> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff73151a8 in _int_free (av=0x7ffff76361c0, p=0x636b00) at
> malloc.c:4973
> 4973    malloc.c: Nie ma takiego pliku ani katalogu.
>         in malloc.c
> (gdb) bt
> #0  0x00007ffff73151a8 in _int_free (av=0x7ffff76361c0, p=0x636b00) at
> malloc.c:4973
> #1  0x00007ffff73189cc in __GI___libc_free (mem=<optimized out>) at
> malloc.c:3738
> #2  0x00007ffff7304365 in _IO_new_fclose (fp=0x636d70) at iofclose.c:
> 88
> #3  0x00007ffff7b4abc0 in std::__basic_file<char>::close() () from /
> usr/lib/x86_64-linux-gnu/libstdc++.so.6
> #4  0x00007ffff7b4e411 in std::basic_filebuf<char,
> std::char_traits<char> >::close() () from /usr/lib/x86_64-linux-gnu/
> libstdc++.so.6
> #5  0x00007ffff7b4ff9d in std::basic_ofstream<char,
> std::char_traits<char> >::close() () from /usr/lib/x86_64-linux-gnu/
> libstdc++.so.6
> #6  0x000000000040478e in main ()

> Compiler is:
> gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)

> is it something obvious? This is a very last instruction in the code.
> I suppose that bugs totaly unrelated to io cause that instruction it
> to fail (overwriting stream's memory or sth like that ) and my code
> requires a general debugging (its quite fresh), but perhaps I am
> wrong.

You're correct - this is extremely unlikely to be a result
of some bug in close() etc. It looks like a typical memory
corruption problem which can be anywhere within your code
executed before the close() call.

If inspection of your code doesn't result in you finding the
bug you could try the 'valgrind' program to help you to find
the reasons.
                              Regards, Jens
-- 
  \   Jens Thoms Toerring  ___      jt@toerring.de
   \__________________________      http://toerring.de

Back to comp.lang.c++ | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

string close causes SIGSEGV Lacek <mateusz.lacki@gmail.com> - 2012-04-18 03:12 -0700
  Re: string close causes SIGSEGV jt@toerring.de (Jens Thoms Toerring) - 2012-04-18 10:32 +0000
  Re: string close causes SIGSEGV Juha Nieminen <nospam@thanks.invalid> - 2012-04-18 11:09 +0000
  Re: string close causes SIGSEGV drew@furrfu.invalid (Drew Lawson) - 2012-04-18 17:50 +0000
    Re: string close causes SIGSEGV gof@somewhere.invalid (Gof) - 2012-04-19 08:05 +0000

csiph-web