Re: [cp-patches] RFC: misc NIO fixes

[Casey Marshall]

On Jul 26, 2005, at 12:42 AM, Mark Wielaard wrote:

> Hi,
>
> On Sat, 2005-07-23 at 20:37 -0700, Casey Marshall wrote:
>
> > Committed. I changed a few minor things, such as using Mark's
> > suggestion to use 'madvise' to load the file into core.
> >
> > I can't get this to work with Jamvm on Darwin; I get a bizarre
> > segfault when trying to create the new MappedByteBufferImpl, and
> > apparently 'mincore' does not work properly if the mapped region is
> > only one page in size. This appears to work fine on GNU/Linux,
> > however, so I'm putting it down to problems with Darwin.
>
> I am seeing the following warnings (which break the build when
> configured with --enable-Werror):
>
> gnu_java_nio_channels_FileChannelImpl.c:565:
>   warning: pointer of type 'void *' used in arithmetic
> gnu_java_nio_channels_FileChannelImpl.c:504:
>   warning: 'RawData_init' may be used uninitialized in this function
> gnu_java_nio_channels_FileChannelImpl.c:503: warning:
>   'MappedByteBufferImpl_init' may be used uninitialized in this  
> function
>
> I have not investigated them yet. But maybe they give a hint to why
> things don't work on darwin?

I doubt it; the segfault disappears if I put a printf printing the  
pointer 'MappedByteBufferImpl_init' before using it to create the new  
buffer. This random kind of behavior makes me guess that I'm  
corrupting memory somehow, but I can't figure out where.

I noticed the warnings, but didn't know we built with Werror; I'll  
fix these.