On Sun, Jan 27, 2013 at 2:26 PM, Ciprian Teodorov < ciprian.teodorov@gmail.com> wrote:
Hi Guys,
Today I wanted to test my TalkFFI project on linux, and I run into some NB issue. It seems that the VM crashes when trying to invoke a function returning a 8 byte structure. I have tried with 4 bytes structure and I get some bogus data but no crash with 12 bytes structure it seems to work...
I suspect this is a win32/linux difference that NB doesn't handle yet. On win32 power-of-two structures <= 8 bytes in length are returned in registers. On linux they're always returned through memory. Here are the relevant defs from the ThreadedIA32FFIPlugin #if defined(_X86_) || defined(i386) || defined(__i386) || defined(__i386__) /* Both Mac OS X x86 and Win32 x86 return structs of a power of two in size * less than or equal to eight bytes in length in registers. Linux never does so. */ # if __linux__ # define WIN32_X86_STRUCT_RETURN 0 # else # define WIN32_X86_STRUCT_RETURN 1 # endif #define returnStructInRegisters(sz) (WIN32_X86_STRUCT_RETURN && (sz) <= 8 && !((sz)&((sz)-1))) HTH Attached to this mail you will find a simple test case.
the c file I have compiled with:
gcc -g -fPIC -Wall -c -m32 strreturn.c gcc -shared -g -Wl,-soname,libret.so.1 -o libret.so -m32 strreturn.o -lc
Cheers, -- Dr. Ciprian TEODOROV Ingénieur Développement CAO
tél : 06 08 54 73 48 mail : ciprian.teodorov@gmail.com www.teodorov.ro
-- best, Eliot