From: hoffman@insync.net (David Hoffman)
Subject: Need Help Calling Ada From C
Date: 1998/12/05
Date: 1998-12-05T00:00:00+00:00 [thread overview]
Message-ID: <hoffman-ya02408000R0512981659060001@news.insync.net> (raw)
Hi,
I am trying to figure out how to call an Ada function from a C program.
For the record I am using GNAT 3.10p on Linux (Slackware, kernel 2.0.33).
I read what I could find on the net, in the GNAT manual, and in several
Ada books that I have. Since I did not find a complete, step-by-step ex-
ample I had to make a few guesses (and maybe that is where things went
wrong).
I created a C program, called fact.c, that calls an Ada function from a
package called first_test (the source code for these items is given at
the end of this message). I compiled this with the commands:
$ gcc -c first_test.ads
$ gcc -c first_test.adb
$ gnatbind -n first_test.ali
$ gcc -c b_first_test.c
$ gcc -c fact.c
I made it this far without any real trouble. Then I got this:
$ gcc -o fact *.o
b_first_test.o: In function `adainit':
b_first_test.o(.text+0x26): undefined reference to `__gnat_set_globals'
b_first_test.o(.text+0x2e): undefined reference to `system__elabs'
b_first_test.o(.text+0x33): undefined reference to
`system__exception_table___elabb'
b_first_test.o(.text+0x38): undefined reference to `interfaces__c___elabs'
b_first_test.o(.text+0x3d): undefined reference to
`system__tasking_soft_links___elabb'
b_first_test.o(.text+0x42): undefined reference to
`system__secondary_stack___elabb'
fact.o: In function `main'
fact.o(.text+0x30): undefined reference to `fact'
Where did I go wrong?
David Hoffman
david.a.hoffman1@jsc.nasa.gov
fact.c --------------------------------------------------------------------
extern void adainit();
extern void adafinal();
extern long factorial( long N );
main (argc, argv)
char *argv[];
int argc;
{
long answer, value;
adainit();
value = atol(argv[1]);
if ( value 0 )
{
if ( value <= 12 )
{
answer = factorial(value);
printf("\n %2d! = %3d\n",value,answer);
}
else
{
printf("\n fact: input value too big (would cause
overflow).\n");
}
}
else
{
printf("\n fact: input must be strictly positive.\n");
}
adafinal();
}
first_test.ads ---------------------------------------------------------
with Interfaces.C; use Interfaces;
package First_Test is
function Factorial ( Value : C.long ) return C.long;
pragma Export (C, Factorial, "factorial");
end First_Test;
first_test.adb ---------------------------------------------------------
with Interfaces.C; use Interfaces;
first_test.adb
package body First_Test is
function Ada_Factorial (N : Integer) return Integer is
begin
if N = 1 then
return 1;
else
return N * Ada_Factorial(N-1);
end if;
end;
function Factorial (Value : C.long) return C.long is
P,Q : Integer;
begin
P := Integer(Value);
Q := Ada_Factorial(P);
return C.long(Q);
end;
end First_Test;
next reply other threads:[~1998-12-05 0:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-12-05 0:00 David Hoffman [this message]
1998-12-09 0:00 ` Need Help Calling Ada From C Mats Weber
1998-12-12 0:00 ` Simon Wright
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