David Mertens wrote:
Hello everybody -
I recently resuscitated CUDA::Minimal, a module that provides basic
memory allocation and memory transfer functionality for CUDA (i.e.
video card) parallel programming. Note, you must write your own CUDA
kernels separately; I recommend writing them in XS wrapper code, using
ExtUtils::nvcc and can answer questions if you're interested.
When using ExtUtils::nvcc, your code gets compiled through a C++
compiler. I seem to have struck a problem with how XS handles its dVAR
and dXSARGS declarations in the Boot section and in other sections.
The applicable error can be found here:
https://github.com/run4flat/perl-CUDA-Minimal/issues/7. The actual C
code that leads to this error (generated from the XS code on my
machine) is given in this gist: https://gist.github.com/run4flat/4974702.
The problem is a linkage conflict in the declaration for Perl__notused
on lines 163
<https://gist.github.com/run4flat/4974702#file-minimal-c-L163> and 329
<https://gist.github.com/run4flat/4974702#file-minimal-c-L374>, which
I presume is embedded in dVAR or dXSARGS. However, I'm left scratching
my head as to why the linkage would differ between these two. Based on
my understanding of how extern "C" works
<http://stackoverflow.com/questions/10458545/what-is-extern-linkage-and-with-c-language-linkage>,
there is no difference that I can see. That is, there is no difference
in the linkage specification for the two, because the extern "C" on
line 369 does not have curly braces and therefore only effects the
declaration of the function definition. It should not impact the
declarations of any variables.
Anybody have any idea what's causing this linkage specification
problem, and how I might fix it?
Thanks!
David
I think dVAR becomes dNOOP which is
http://perl5.git.perl.org/perl.git/blob/f6fe275c937ceb508cdcfd033ce162e1fa01989e:/perl.h#l354.
Note a C++ and a C version of that macro. Can you post the preprocessed
version of the .c file or have you looked at the preprocessed version
for clues as to what happened?
