Q: Howto use the C interfaces of Ada

Q: Howto use the C interfaces of Ada

[Erik Margraf]

I have a little question on using the C language interfaces
of Ada (using GNAT 3.10p on Linux, but I think that doesn't matter
that much in this case). 
I basically tried to do the equvalent Ada code for the following 
C code (It may be not 100% correct, because I didnt copy it from 
the sources)

  ...
   struct hostent *h;
   struct sockaddr_in addr;
   h = gethostbyname("some_hostname");

   memcpy(&addr.sin_addr, h->h_addr, h->h_length);
  ...

The difficulties I have lie in the definition of the "Ada" hostent
structure and then of course the right "memcpy" statement.
I tried something like the following.
  type hostent is record
     h_name : interfaces.C.Strings.chars_ptr;
     h_aliases : interfaces.C.strings.chars_ptr_array; -- ???
     h_addrtype : interfaces.C.int;
     h_length : interfaces:C.int;
     h_addr_list : interfaces.C.strings.chars_ptr_array; -- ???
  end record;   

I think I did the definition of the sockaddr_in type right, because 
when I hardcoded the address, the bind call worked. Also h_name, 
h_addr_type and h_length were OK. But I could not get the the address
information from the hostent record.

Thanks in advance for any help.

Erik Margraf
-- 
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--   Erik Margraf                SIEMENS Austria, PSE KB24    --
--   erik.margraf@siemens.at                                  --
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