Re: GNAT GPL 2005 Edition is now available

[Samuel Tardieu <sam@rfc1149.net>]

>>>>> "Ludovic" == Ludovic Brenta <ludovic@ludovic-brenta.org> writes:

Ludovic> In fact, you could install GNAT GPL and libgnat GMGPL
Ludovic> separately, and use them together.  This may require some
Ludovic> tweaking, but it is feasible.  I think that the tweaking
Ludovic> would be minimal if you mix GNAT GPL 2005 Edition with
Ludovic> libgnat-3.4.

This would be highly risky. For those who do not know the compilation
process of GNAT, here is a short overview.

Complex Ada constructs cannot be translated into a *short* sequence of
machine code. While basic operations such as

  A + B * C

are translated into a few arithmetic operations (I'm purposely
skipping range checking considerations here) by the GNAT compiler,
task creation or task priority manipulation require complex
operations.

The GNAT compiler doesn't try to directly generate machine code for
those complex operations. It replaces them by calls to the runtime
library, which will perform its duties, such as allocating memory for
tasks (task control block, stack space, ...) or inserting the task
at the right place into the scheduler.

While replacing the standalone library packages (such as Ada.Text_IO)
with other versions is almost straightforward and is not likely to
lead to bogus behaviour, replacing the runtime tasking library by
another version which may not *exactly* match the output produced by
the compiler is very unsafe and may cause hard-to-catch errors.

  Sam
-- 
Samuel Tardieu -- sam@rfc1149.net -- http://www.rfc1149.net/sam