Re: Import a type from C

["Frank J. Lhota" <NOSPAM.lhota.adarose@verizon.net>]

Thinking over my previous experience with this type of work, I would go with
the advice of using a representation clause. In general, a representation
clause should be used whenever a type cooresponds to data external to the
Ada program. This eliminates any concern about how this or that compiler
lays out a record.

Ada programmers are blessed with the whole chapter 13 support. C / C++ has
only the crude pack pragma / command line option to control the layout of a
struct. Is there any C compiler that automatically generates a decription of
how it lays out a struct? If I declare

    typedef struct tag_mydata {
        char     lead;
        long     total;
        unsigned year  : 12;
        unsigned month :  4;
        unsigned day   :  5;
        } mydata;

is there a C compiler that has a command line option that will generate a
listing that shows the byte offset of the total member from the start of a
"mydata" struct, or the location of the bits that make up the month member?
Neither gcc nor MSVC++ has such an option, which would make this work much
easier.