Den 2011-04-11 09:19 skrev Alex Peshkoff såhär: > I'm far not sure everything is so fine with that structure/class. Look here: > unsigned > blrLength; > > const unsigned char* blr; > Pointer (8-bytes object) is placed after integer (4-bytes object). C > language has a requirement to align it on 8-bytes boundary, but what > about others? I't quite possible that some other language will try to > save memory. The result is obvious - segfault when we use such structure.
1. This is a doc issue more than anything. There's always a workaround, e.g. insering dummy fields in a language that uses "packed" recs/structs. Just make sure you document the binary format complete with alignment/padding. 2. If I'm not mistaken most languages support a "packed" directive that tells the compiler to not align/pad the struct. Delphi does. But I doubt it's possible to do the other way around: tell a compiler to pad/align to N bytes. So, perhaps the most compatible way is to use packed structs everywhere. On the other hand, this will probably induce a performance hit - that's why alignment is used at all. Kjell -- -------------------------------------- Kjell Rilbe DataDIA AB E-post: kj...@datadia.se Telefon: 08-761 06 55 Mobil: 0733-44 24 64 ------------------------------------------------------------------------------ Xperia(TM) PLAY It's a major breakthrough. An authentic gaming smartphone on the nation's most reliable network. And it wants your games. http://p.sf.net/sfu/verizon-sfdev Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
