Re: [Boost-users] [interprocess] Segmentation fault when using std::string in stl::maps in shared memory

Subject: Re: [Boost-users] [interprocess] Segmentation fault when using std::string in stl::maps in shared memory
From: hamsinv (hamsinv_at_[hidden])
Date: 2008-10-20 23:39:49

Thank you for the pointer. Could you please explain how to use
boost::interprocess::string.

Regards

Ravi-41 wrote:
> 
> On Monday 20 October 2008 02:38:05 hamsinv wrote:
>> After a few search I found out that we cannot use std::string. Instead we
>> should try with interprocess::basic_string. Can anyone guide me through
>> this.
> 
> The fundamental issue is that objects which allocate memory on the heap
> cannot 
> be used with shared memory. Consider what happens when you use a construct
> a 
> string in shared memory. Upon construction which requires storage (such as 
> assigning it an initial value), the string constructor allocates some
> memory 
> on the heap (not in the shared memory segment), which is visible only in
> the 
> constructing process. Using the memory in the other processes tries to
> access 
> those memory locations which results in undefined behavior. In order to 
> overcome this problem, you need to use a shared-memory-aware string, such
> as 
> interprocess::basic_string.
> 
> Please read the section named "Limitations When Constructing Objects In
> Mapped 
> Regions" in the interprocess manual for more information.
> 
> Regards,
> Ravi
> 
> 
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> 

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