A program I'm building connects to a (Cygwin) server and receives the
address of a shared memory segment. The memory contains an array of struct
and you probably know that Microsoft (by default) aligns structure members
on 8-byte boundaries (sometimes called 8-byte packing).
As things stand, both client and server use System V shared memory and
everything works well if I compile under Cygwin or Linux. Ultimately
however, there'll be no Linux clients. The clients will either be Cygwin
clients or Windows clients. Therefore I'm currently experimenting to see if
I can change the server to use Windows shared memory (only under Cygwin of
course - not for Linux use).
This all seems to be going well - but I was surprised to find that I need to
compile the Windows clients using MSVC's default (8-byte) struct alignment.
I'd assumed that Cygwin probably wouldn't use structure packing (only
because I don't think Linux does). But I only get meaningful data with
8-byte packing. It looks as if Cygwin's compiler must default to 8-byte
packing too. Does that make sense?
Thanks,
John
--
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Problem reports: http://cygwin.com/problems.html
Documentation: http://cygwin.com/docs.html
FAQ: http://cygwin.com/faq/
