>> Interesting to know, apparently native alignment is 8 on X86_64 linux >> and 4 on armhf linux. That's why it worked on X86_64. >> >> Regarding python ctypes module, setting _pack_=8 has no remedy effect on >> armhf platform, so I'll move to struct module. Hi, tying some loose ends here. My final solution to force alignment after bcm_msg_head to the next 8 byte boundary in python3 is to use an alignment hack of struct module. https://docs.python.org/3/library/struct.html#struct-examples struct.pack("IIIllllII0q",opcode,flags,count,ival1_sec,ival1_usec,ival2_sec,ival2_usec,can_id,nframes) The "0q" is a zero length long long which causes padding up to the next 8 byte boundary. This works for ARMHF (40 bytes) and X86_64 (72 bytes). Regards, Patrick
