Re: [boost] [iostreams] mapped_file trouble

From: Dylan Trotter (trotterdylan_at_[hidden])
Date: 2005-08-24 23:12:18

Pardon me, correction:

Dylan Trotter wrote:
> Hi,
> 
> I just wanted to point out a fairly major flaw with the Windows 
> implementation of memory mapped files. In memory_mapped.cpp on line 

*mapped_file.cpp*, not memory_mapped.cpp

> 205-207 a file mapping is created as follows:
> 
>          ::CreateFileMappingA( pimpl_->handle_, NULL,
>                                readonly ? PAGE_READONLY : PAGE_READWRITE,
>                                0, 0, p.path.c_str() );
> 
> The problem with this is that if p.path.c_str() has any backslashes in 
> it (very likely given that it's Windows), the call fails. From the MS 
> documentation:
> 
> "Windows NT:  The name can contain any character except the backslash 
> character.
> Windows Me/98/95:  The name can contain any character except the 
> backslash character. The empty string ("") is a valid object name."
> 
> Also from the documentation:
> 
> "If this parameter is NULL, the mapping object is created without a name."
> 
> Given that there's no way to access named memory maps from the boost 
> interface anyway, it seems pointless to name the mapping. My suggestion 
> is to pass in NULL and avoid naming difficulties altogether.
> 
> Thanks,
> 
> Dylan Trotter
> 
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