[Boost-bugs] [Boost C++ Libraries] #11072: [iostreams] mapped_file::size() returns the wrong size on 32-bit windows platforms for files larger than 4gb

Subject: [Boost-bugs] [Boost C++ Libraries] #11072: [iostreams] mapped_file::size() returns the wrong size on 32-bit windows platforms for files larger than 4gb
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-03-05 12:12:46

#11072: [iostreams] mapped_file::size() returns the wrong size on 32-bit windows
platforms for files larger than 4gb
---------------------------------------------+-----------------------
 Reporter:  James Whitworth <fun4jimmy@…>    |      Owner:  turkanis
     Type:  Bugs                             |     Status:  new
Milestone:  To Be Determined                 |  Component:  iostreams
  Version:  Boost 1.57.0                     |   Severity:  Problem
 Keywords:  mapped_file size 32-bit windows  |
---------------------------------------------+-----------------------
 The signature is size_t mapped_file::size() which is uint32_t for 32-bit
 builds. This means files larger than 4gb will return an incorrect value.

 Looking at the windows implementation source for mapped_file
 https://github.com/boostorg/iostreams/blob/master/src/mapped_file.cpp

 around line 220. The size is queried and stored as a local boost::intmax_t
 but when assigning to size_ it is static_cast to the smaller type.

 I think the fix is to change the size member to be always 64-bit but I'm
 not familiar enough with the rest of the library to know if this would
 have any knock on effects. I suspect this is also an issue on linux as
 well but I am unable to easily test that at the moment,

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11072>
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