malloc: *** error for object: incorrect checksum for freed object

[Fabian Schuiki]

Solved the problem... Variable not initialized.

Best,
Fabian

Fabian Schuiki
fabianschuiki at bluewin.ch


Am 04.01.2008 um 00:23 schrieb Fabian Schuiki:

> Hi everyone!
>
> I'm not that experienced with C++, but in most cases, my code works  
> as intended.
> Now I've encountered the following error:
>
> "malloc: *** error for object 0x129d90: incorrect checksum for freed  
> object - object was probably modified after being freed"
>
> This happens in this code segment (at least I tracked down the error  
> to this segment):
>
> //Remove all whitespaces
> std::string str = input;
> std::string sub = " ";
> std::string rep = "";
> std::string::size_type pos = str.find(sub, 0);
> int len = sub.length();
> while (std::string::npos != pos)
> {
> 	str.replace(pos, len, rep);
> 	pos = str.find(sub, pos);
> }
>
> It seems to be the line
>
> 	str.replace(pos, len, rep);
>
> that causes the problem — if I comment it out, the error message  
> disappears.
> If I set a breakpoint in "malloc_error_break" as the error suggests,  
> the debugger breaks somewhere in NSApplicationMain:
>
> #0	0x91280060 in malloc_error_break
> #1	0x9127acc8 in szone_error
> #2	0x91173078 in tiny_free_list_add_ptr
> #3	0x9116fc20 in szone_free
>
> #4	0x90046a5c in std::_Rb_tree<void const*, std::pair<void const*  
> const, NotificationInformationStruct*>,  
> std::_Select1st<std::pair<void const* const,  
> NotificationInformationStruct*> >, std::less<void const*>,  
> std::allocator<std::pair<void const* const,  
> NotificationInformationStruct*> > >::destroy_node
>
> #5	0x90046af4 in std::_Rb_tree<void const*, std::pair<void const*  
> const, NotificationInformationStruct*>,  
> std::_Select1st<std::pair<void const* const,  
> NotificationInformationStruct*> >, std::less<void const*>,  
> std::allocator<std::pair<void const* const,  
> NotificationInformationStruct*> > >::_M_erase
>
> #6	0x90046ae4 in std::_Rb_tree<void const*, std::pair<void const*  
> const, NotificationInformationStruct*>,  
> std::_Select1st<std::pair<void const* const,  
> NotificationInformationStruct*> >, std::less<void const*>,  
> std::allocator<std::pair<void const* const,  
> NotificationInformationStruct*> > >::_M_erase
>
> #7	0x90046bcc in std::_Rb_tree<void const*, std::pair<void const*  
> const, NotificationInformationStruct*>,  
> std::_Select1st<std::pair<void const* const,  
> NotificationInformationStruct*> >, std::less<void const*>,  
> std::allocator<std::pair<void const* const,  
> NotificationInformationStruct*> > >::~_Rb_tree
>
> #8	0x9117c2ac in __cxa_finalize
> #9	0x9117c188 in exit
> #10	0x936569d8 in NSApplicationMain
> #11	0x00002784 in main at main.mm:14
>
>
> After this code segment which is supposed to remove all whitespaces  
> in the string "input", there are several substrings taken from the  
> string "str" and are then filled into a std::map.
> There are actually 4 key-value-pairs in the final std::map. The  
> stack trace also lists 4 entries that seem to be related to  
> std::pair — maybe this is a clue.
>
>
> Does anyone know what the solution could be for this problem?
>
> Thanks in advance,
> Happy New Year,
> Fabian
>
>
> Fabian Schuiki
> fabianschuiki at bluewin.ch
>
>
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