Suppose we have a Prolog source file ex.pl
containing:
% ex.plforeign(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 long
and having a
long
as only parameter. The conversion declarations in
ex.pl
state that these functions form the foreign resource
ex
.
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. Linked foreign resources can also be
created manually (see Runtime Utilities).
Dynamic linking of foreign resources can also be used by runtime systems. On some platforms, however, the executable must not be stripped for dynamic linking to work, i.e. its symbol table must remain.