Re: Interfacing with C - pointer problem

[tmoran@acm.org]

>   type LPSTR is access all String;
>
> This does not work correct. What I found is, that data'Address is 32
> bit and LPSTR is 64 bit.
   Because LPSTR points to a dynamic size string and thus needs to
carry along bounds information.  A C LPSTR does not point to a dynamic
string, but instead points to a single character - the first in the
string.  So the match is
   type LPSTR is access Interfaces.C.Char;
   procedure C_Func (x : LPSTR);  -- expects an address (C-pointer, 32-bit)
and then
   data : Interfaces.C.char_array := Interfaces.C.To_C("ABC");
and
   C_Func (data(data'first)'unchecked_access);