Re: [Boost-users] [interprocess] file_mapping/mapped_region on empty file throws?

Ion Gaztañaga wrote:

On 29/11/2010 19:05, Jeff Flinn wrote:

...

The following appears to throw an interprocess_exception with boost_1_44_0 compiled with MSVC8 running on windows XP.

using namespace boost::interprocess;

file_mapping fm("empty.txt", read_only); mapped_region mr( fm, read_only);

Is there a reason I can't just get back a null address and zero size?

It's common practice not to support empty mappings. Windows mapped files don't support an empty file. In Unix, mapping zero bytes is an error:

http://www.opengroup.org/onlinepubs/009695399/functions/mmap.html

"If len is zero, mmap() shall fail and no mapping shall be established"

Thanks Ion. I'll just deal with the exception appropriately then. Jeff