On Feb 20, 2013, at 12:37 PM, Ralph Castain <r...@open-mpi.org> wrote:

>> In Java, a long is always 64 bits. In C and Objective-C, a long might be 64 
>> bits, or it might be 32 bits, or (in less common cases) it might be 
>> something else entirely; the C standard doesn't specify an exact bit width.
> 
> So we may need a configure test to map the Java "long" data type to the right 
> thing to get int64_t?

I think we might have to end up doing what we did for fortran: a bunch of 
configure tests to map Java types to their corresponding C types.

I have no idea how to write such configure tests, though, because it involves 
writing java code. The way it works in the Fortran tests is that we write a 
simple program (that's usually a combination of Fortran and C) to figure out 
the size of a given fortran datatype.  Then we have shell/m4 code to match that 
with a corresponding C type.

If someone could write some generic java code to figure out the size of a java 
type (and either printf it out, or write it to a file, or otherwise be able to 
give that value to a shell script), that would be a good start.

-- 
Jeff Squyres
jsquy...@cisco.com
For corporate legal information go to: 
http://www.cisco.com/web/about/doing_business/legal/cri/


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