* gnat : descendents of package System may not be compiled error
@ 2011-05-23 15:34 milouz
2011-05-23 15:45 ` Robert A Duff
0 siblings, 1 reply; 3+ messages in thread
From: milouz @ 2011-05-23 15:34 UTC (permalink / raw)
Hi,
I'm pretty new with Ada programming and I have a little problem.
I want to write a very small kernel. So, I can't use the standard
adainclude and adalib. Then, I created my own include directory (named
sys/). I put in it some very few packages :
$ ls sys/
ada.ads a-unccon.ads interfac.ads s-expint.adb s-expint.ads s-
stoele.adb s-stoele.ads system.ads
And everything compiled and worked fine. But then, I created a
function that use the exponentiation '**' operator. But now, when I
try to compile my kernel :
$ make
...
$ gcc -m32 -gnato -gnatf -fstack-check -nostdinc -nostdlib -Isys/ -c
lib.adb
lib.adb:24:33: run-time library configuration error
lib.adb:24:33: file s-expint.ads not found
lib.adb:24:33: entity "System.Exp_Int.Exp_Integer" not available
compilation abandoned
Ok, gnat complains about a missing lib. It's a bit odd that '**' needs
a lib to be implemented !!!
Anyway, I copy s-expint.ad* in sys/ directory (which contains runtime
library suitable for my kernel) :
$ cp /opt/gcc-4.4.5/lib/gcc/x86_64-unknown-linux-gnu/4.4.5/32/
adainclude/s-expint* sys/
$ gcc -m32 -gnato -gnatf -fstack-check -nostdinc -nostdlib -Isys/ -c
lib.adb
$ ld -m elf_i386 --oformat binary -Ttext 1000 -e_ada_kernel kernel.o
video.o exceptions.o lib.o -o kernel
lib.o: In function `lib__integer_to_ascii':
lib.adb:(.text+0x1e4): undefined reference to
`system__exp_int__exp_integer'
Mmmh.... the linker can't find Exp_Integer function which is defined
in sys/s-expint.adb. I logicaly have to compile it to generate a .o
object with the `system__exp_int__exp_integer' function.
$ gcc -m32 -gnato -gnatf -fstack-check -nostdinc -nostdlib -Isys/ -c
sys/s-expint.adb
s-expint.adb:32:01: descendents of package System may not be
compiled
Another error ! But now, it looks like a dead end as Gnat don't want
me to compile it with no other reason than the package name !!!
A kludge is to define that function in another package and to export
it via that kind of pragma : pragma Export(C, my_exp_int,
"system__exp_int__exp_integer").
But redefining that function in another package is really ugly.
Perhaps there's something I missed, but if someone have an explanation
and a solution, it would be very great :-)
Regards,
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2011-05-23 15:34 gnat : descendents of package System may not be compiled error milouz
2011-05-23 15:45 ` Robert A Duff
2011-05-23 16:38 ` milouz
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