[Swig-devel] [ swig-Bugs-2965875 ] int64_t defined incorrectly

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Bugs item #2965875, was opened at 2010-03-08 22:04
Message generated for change (Comment added) made by ebf
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Category: java
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Eric Friedman (ebf)
Assigned to: William Fulton (wsfulton)
Summary: int64_t defined incorrectly

Initial Comment:
Hi,

I am using SWIG 1.3.39 and GCC 4.4.1 (Ubuntu 4.4.1-4ubuntu9) on Ubuntu 9.10 (Linux efriedma-ux 2.6.31-19-generic #56-Ubuntu SMP Thu Jan 28 02:39:34 UTC 2010 x86_64 GNU/Linux).

Normally on 64-bit Linux, int64_t is defined to be a `long int`. However, in SWIG (at least for Java), it is defined incorrectly, as seen in the following simple interface file:

   // foo.i
   %module foo
   %{
   #include <boost/static_assert.hpp>
   #include <boost/type_traits/is_same.hpp>
   BOOST_STATIC_ASSERT(( boost::is_same<int64_t, jlong>::value ));
   %}

This may be compiled as follows:

   $ swig -c++ -java foo.i
   $ g++ foo_wrap.cxx
   foo_wrap.cxx:216: error: invalid application of 'sizeof' to incomplete type 'boost::STATIC_ASSERTION_FAILURE<false>'

The error means the Boost static assertion has failed, which indicates that `int64_t` and `jlong` are not the same type. (The result is the same even if I include the SWIG import <stdint.i>.)

However, the following C++ program, which has the same check compiles without a problem:

   #include <boost/static_assert.hpp>
   #include <boost/type_traits/is_same.hpp>
   int main()
   {
      BOOST_STATIC_ASSERT(( boost::is_same<int64_t, jlong>::value ));
      return 0;
   }

Trying to track this down, it seems as though the problem is due to the following lines in the SWIG-generated source file (foo_wrap.cxx):

   /* Fix for jlong on 64-bit x86 Solaris */
   #if defined(__x86_64)
   # ifdef _LP64
   #   undef _LP64
   # endif
   #endif

Doing this causes the JNI headers to make the `jlong` type as a typedef for `long long int`. I don't understand why this is being done, as it's different from `int64_t`.

Thanks,

Eric

P.S. Looking at the Subversion history for this change, I came across the following:

http://swig.svn.sourceforge.net/viewvc/swig?view=rev&revision=6891

The commit message (from marcelomatus) is "fix warning(error?) with jlong + x86_64". Does that give any clue as to why this introduced? Are there other problems with SWIG on 64-bit platforms? (The uncertainty in the commit message is a bit unnerving.)

----------------------------------------------------------------------

>Comment By: Eric Friedman (ebf)
Date: 2010-03-08 22:05

Message:
Also forgot to mention: I also checked with the latest version of SWIG
(1.3.40), and it seems that this issue is still present there as well.

----------------------------------------------------------------------

You can respond by visiting: 
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