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Porting from version 1 to version 2 |
The easiest way of porting from SWI-cpp.h
to SWI-cpp2.h
is to change the #include "SWI-cpp.h"
to #include
"SWI-cpp2.h"
and look at the warning and error messages. Where
possible, version 2 keeps old interfaces with a “deprecated” flag
if there is a better way of doing things with version 2.
For convenience when calling PL_*() functions, the Plx_*() wrapper
functions add error checking. Also, most of the PL_*() functions that
work with term_t
, atom_t
, etc. have
corresponding methods in PlTerm
, PlAtom
, etc.
Here is a list of typical changes:
term_t
, PlTerm_integer(i),
PlTerm_float(v), or PlTerm_pointer(p).
char*
or wchar_t
and
replace them by
std::string
or std::wstring
if appropriate.
For example, cout << "Hello " << (char*)A1 <<
endl
can be replaced by cout << "Hello " << A1.as_string()
<< endl
. In general, std::string
is safer than char*
because the latter can potentially point to freed memory.
false
from a predicate for
failure, you can do throw PlFail()
. This mechanism
is also used by
PlCheckFail(rc). Note that
throwing an exception is slower than returning false
, so
performance-critical code should avoid PlCheckFail(rc)
if failure is expected to happen often.
SWI-Prolog
and throw a PlFail
exception to short-circuit execution and return failure (false
)
to Prolog (or throw a PlException
if there was a Prolog
error.
PlAtom::handle
has been replaced by PlAtom::C_
,
which should be accessed by PlAtom::unwrap().
PlTerm::ref
has been replaced by PlTerm::C_
,
which should be accessed by PlTerm::unwrap().
PlFunctor::functor
has been replaced by PlFunctor::C_
,
which should be accessed by PlFunctor::unwrap().
=
for unification has been
deprecated, replaced by various unify_*() methods (PlTerm::unify_term(t2),
PlTerm::unify_atom(a),
etc.).
static_cast<char*>(t)
is replaced by t.as_string().c_str()
(and you should prefer t.as_striong()
;
static_cast<int32_t>(t)
is replaced by t.as_int32_t()
,
etc.
int
or
long
because of problems porting between Unix and Windows
platforms; instead, use int32_t
, int64_t
,
uint32_t
, uint64_t
, etc.