Re: Using GNU make with ObjectAda

["Robert I. Eachus" <rieachus@attbi.com>]

Ludovic Brenta wrote:

> In Ada, you have the concept of a "library" of compilation units
> (packages or subprograms that are "at library level"); the Ada
> compiler is in charge of maintaining this library and making sure the
> units it contains remain consistent with one another.  It is this
> "library" that lets the compiler keep track of where source files are.

(If you are not a language lawyer, you can skip the rest of this post.)

No, the Ada compiler is responsible for identifying a set of consistant 
library units that the unit being compiled depends on, and insuring that 
the closure of that set at run-time is consistant.  It is perfectly 
legal for the library to contain mutually inconsistant library units and 
subunits.

The usual effect of this rule is that at "link time" which is not an Ada 
term, the implementation recognizes inconsistancies and causes the 
necessary units to be recompiled.  (With GNAT, this is the job of 
gnatmake, to find out what is inconsistant and call the compiler on 
those units in an order consistant with the language rules.)

But as I said at the beginning, only language lawyers need think about 
the fact that a library unit, body, or subunit may be inconsistant with 
library units it does not depend on.  (For example, during a series of 
compilations.)

-- 
                                               Robert I. Eachus

"As far as I'm concerned, war always means failure." -- Jacques Chirac, 
President of France
"As far as France is concerned, you're right." -- Rush Limbaugh