The problem of sending raw structs is one (or two) issues known as
Endian
Endianness - Wikipedia, the free encyclopedia
Alignment
Data structure alignment - Wikipedia, the free encyclopedia
Fixing alignment is generally possible with "#pragma pack" kludges and the like.
Fixing endian is an altogether much harder problem. Typically, you should use the htons() and similar functions to ensure that multi-byte data types are consistently represented on the wire.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
I was aware of the first issue but the second one took me by surprise.Originally Posted by Salem
These datagrams I'm sending travel only within LAN confines and only between matched client-server pairs. What I seem to be discovering is that data alignment varies even between windows versions... some of the servers on XP some on Windows 7 ... While the whole thing mostly works, I still get the odd time when a smaller datagram isn't sent. (I have "sniffed" it and it is not being sent)
The pragma doesn't appear to help much as there are still datagrams that don't get sent.
As is so common in the computer industry I appear to have tripped over convenience here. I'm presently experimenting with different ideas to see which works best...
Thanks to you also for an informative reply.
