Re: Passing an Ada array to a C function

["David Botton" <David@Botton.com>]

procedure My_C_Func (S : Interfaces.C.char_array);
pragma Import (C, My_C_Func);

is equal to

void My_C_Func (char* s);

A Char_Array contains more information than a char* and does not per se
occupy the same number of bytes, but take a look at the ref manual where it
describes that compilers must make the above possible.

The Ada interface to C in most code and bindings I have seen highly
underused. There is all kinds of neat stuff you can do by just setting up
the procedure specs properly. Take a look at the body of some of the
GWindows packages (http://www.adapower.com/gwindows) for some good ideas. I
chose not to write a set stand alone thin Win32 bindings since that would
cripple the power of the Ada interface to C and instead tailored each import
spec in the function body to match what I wanted to accomplish.

David Botton



----- Original Message -----
From: "Lin" <lin@post.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Monday, September 10, 2001 9:21 PM
Subject: Passing an Ada array to a C function


> If an Ada array holds the pointers pointing to a String (char_array),
> how can I pass the Ada array to an C funtion with an array as formal
> parameter? Is the "char_array" of Ada occupies the same bytes as the
> "char" of C?
>
> Many thnks.
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