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Suppose we have a Prolog source file ex.pl
containing:
% ex.pl
foreign(f1, p1(+integer,[-integer])). foreign(f2, p2(+integer,[-integer])). foreign_resource(ex, [f1,f2]). :- load_foreign_resource(ex).
and a C source file ex.c
with definitions of the functions
f1
and f2
, both returning SP_integer
and having an
SP_integer
as the only parameter. The conversion declarations in
ex.pl state that these functions form the foreign resource
ex
. Normally, the C source file should contain the following
two line near the beginning (modulo the resource name):
#include <sicstus/sicstus.h> /* ex_glue.h is generated by splfr from the foreign/[2,3] facts. Always include the glue header in your foreign resource code. */ #include "ex_glue.h"
To create the linked foreign resource, simply type (to the Shell):
% splfr ex.pl ex.c
The linked foreign resource ex.so (file suffix .so
is system dependent) has been created. It will be dynamically linked by
the directive :- load_foreign_resource(ex).
when the file
ex.pl is loaded. For a full example, see Foreign Code Examples.
Dynamic linking of foreign resources can also be used by runtime systems.