ST(0) = newSVpv("Hello World",0);
sv_2mortal(ST(0));
XSRETURN(1);
-
+
SV *
beta()
CODE:
is not properly decremented. Thus, the above XSUB would leak memory
whenever it is being called. The same problem exists for C<HV *>.
-When you're returning an C<AV *> or a C<HV *>, you have make sure
+When you're returning an C<AV *> or a C<HV *>, you have to make sure
their reference count is decremented by making the AV or HV mortal:
AV *
is quietly ignored.
The following code demonstrates how to supply initialization code for
-function parameters. The initialization code is eval'd within double
+function parameters. The initialization code is eval'ed within double
quotes by the compiler before it is added to the output so anything
which should be interpreted literally [mainly C<$>, C<@>, or C<\\>]
must be protected with backslashes. The variables $var, $arg,
bool_t
rpcb_gettime(host,timep)
- char *host = (char *)SvPV($arg,PL_na);
+ char *host = (char *)SvPV_nolen($arg);
time_t &timep = 0;
OUTPUT:
timep
bool_t
rpcb_gettime(host,timep)
- time_t &timep ; /* \$v{timep}=@{[$v{timep}=$arg]} */
- char *host + SvOK($v{timep}) ? SvPV($arg,PL_na) : NULL;
+ time_t &timep; /* \$v{timep}=@{[$v{timep}=$arg]} */
+ char *host + SvOK($v{timep}) ? SvPV_nolen($arg) : NULL;
OUTPUT:
timep
If one of the input arguments to the C function is the length of a string
argument C<NAME>, one can substitute the name of the length-argument by
-C<length(NAME)> in the XSUB declaration. This argument must be omited when
+C<length(NAME)> in the XSUB declaration. This argument must be omitted when
the generated Perl function is called. E.g.,
void
time_t timep = NO_INIT
PREINIT:
char *host = "localhost";
- STRLEN n_a;
CODE:
if( items > 1 )
- host = (char *)SvPV(ST(1), n_a);
+ host = (char *)SvPV_nolen(ST(1));
RETVAL = rpcb_gettime( host, &timep );
OUTPUT:
timep
time_t timep;
bool_t x;
CODE:
- ST(0) = sv_newmortal();
if( rpcb_gettime( host, &timep ) ){
+ ST(0) = sv_newmortal();
sv_setnv( ST(0), (double)timep);
}
else{
VERSIONCHECK: DISABLE
+Note that if the version of the PM module is an NV (a floating point
+number), it will be stringified with a possible loss of precision
+(currently chopping to nine decimal places) so that it may not match
+the version of the XS module anymore. Quoting the $VERSION declaration
+to make it a string is recommended if long version numbers are used.
+
=head2 The PROTOTYPES: Keyword
The PROTOTYPES: keyword corresponds to B<xsubpp>'s C<-prototypes> and
PROTOTYPE: $;$
PREINIT:
char *host = "localhost";
- STRLEN n_a;
CODE:
if( items > 1 )
- host = (char *)SvPV(ST(1), n_a);
+ host = (char *)SvPV_nolen(ST(1));
RETVAL = rpcb_gettime( host, &timep );
OUTPUT:
timep
In this case, the function will overload both of the three way
comparison operators. For all overload operations using non-alpha
-characters, you must type the parameter without quoting, seperating
+characters, you must type the parameter without quoting, separating
multiple overloads with whitespace. Note that "" (the stringify
overload) should be entered as \"\" (i.e. escaped).
C<subtract_off>. Then one can use
#define XSINTERFACE_FUNC_BYOFFSET(ret,cv,f) \
- ((XSINTERFACE_CVT(ret,))fp[CvXSUBANY(cv).any_i32])
+ ((XSINTERFACE_CVT_ANON(ret))fp[CvXSUBANY(cv).any_i32])
#define XSINTERFACE_FUNC_BYOFFSET_set(cv,f) \
CvXSUBANY(cv).any_i32 = CAT2( f, _off )
T_PTROBJ_SPECIAL
if (sv_derived_from($arg, \"${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")) {
IV tmp = SvIV((SV*)SvRV($arg));
- $var = ($type) tmp;
+ $var = INT2PTR($type, tmp);
}
else
croak(\"$var is not of type ${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")
on the fly, giving the desired effect. This example demonstrates some
of the power and versatility of the typemap facility.
+The INT2PTR macro (defined in perl.h) casts an integer to a pointer,
+of a given type, taking care of the possible different size of integers
+and pointers. There are also PTR2IV, PTR2UV, PTR2NV macros,
+to map the other way, which may be useful in OUTPUT sections.
+
=head2 Safely Storing Static Data in XS
Starting with Perl 5.8, a macro framework has been defined to allow
dMY_CXT;
CODE:
if (MY_CXT.count >= 3) {
- warn("Already have 3 blind mice") ;
+ warn("Already have 3 blind mice");
RETVAL = 0;
}
else {
else
RETVAL = newSVpv(MY_CXT.name[index - 1]);
+ void
+ CLONE(...)
+ CODE:
+ MY_CXT_CLONE;
B<REFERENCE>
The MY_CXT_INIT macro initialises storage for the C<my_cxt_t> struct.
-It I<must> be called exactly once -- typically in a BOOT: section.
+It I<must> be called exactly once -- typically in a BOOT: section. If you
+are maintaining multiple interpreters, it should be called once in each
+interpreter instance, except for interpreters cloned from existing ones.
+(But see C<MY_CXT_CLONE> below.)
=item dMY_CXT
dMY_CXT;
MY_CXT.index = 2;
+=item aMY_CXT/pMY_CXT
+
+C<dMY_CXT> may be quite expensive to calculate, and to avoid the overhead
+of invoking it in each function it is possible to pass the declaration
+onto other functions using the C<aMY_CXT>/C<pMY_CXT> macros, eg
+
+ void sub1() {
+ dMY_CXT;
+ MY_CXT.index = 1;
+ sub2(aMY_CXT);
+ }
+
+ void sub2(pMY_CXT) {
+ MY_CXT.index = 2;
+ }
+
+Analogously to C<pTHX>, there are equivalent forms for when the macro is the
+first or last in multiple arguments, where an underscore represents a
+comma, i.e. C<_aMY_CXT>, C<aMY_CXT_>, C<_pMY_CXT> and C<pMY_CXT_>.
+
+=item MY_CXT_CLONE
+
+By default, when a new interpreter is created as a copy of an existing one
+(eg via C<< threads->create() >>), both interpreters share the same physical
+my_cxt_t structure. Calling C<MY_CXT_CLONE> (typically via the package's
+C<CLONE()> function), causes a byte-for-byte copy of the structure to be
+taken, and any future dMY_CXT will cause the copy to be accessed instead.
+
+=item MY_CXT_INIT_INTERP(my_perl)
+
+=item dMY_CXT_INTERP(my_perl)
+
+These are versions of the macros which take an explicit interpreter as an
+argument.
+
=back
+Note that these macros will only work together within the I<same> source
+file; that is, a dMY_CTX in one source file will access a different structure
+than a dMY_CTX in another source file.
+
+=head2 Thread-aware system interfaces
+
+Starting from Perl 5.8, in C/C++ level Perl knows how to wrap
+system/library interfaces that have thread-aware versions
+(e.g. getpwent_r()) into frontend macros (e.g. getpwent()) that
+correctly handle the multithreaded interaction with the Perl
+interpreter. This will happen transparently, the only thing
+you need to do is to instantiate a Perl interpreter.
+
+This wrapping happens always when compiling Perl core source
+(PERL_CORE is defined) or the Perl core extensions (PERL_EXT is
+defined). When compiling XS code outside of Perl core the wrapping
+does not take place. Note, however, that intermixing the _r-forms
+(as Perl compiled for multithreaded operation will do) and the _r-less
+forms is neither well-defined (inconsistent results, data corruption,
+or even crashes become more likely), nor is it very portable.
+
=head1 EXAMPLES
File C<RPC.xs>: Interface to some ONC+ RPC bind library functions.
https://perl5.git.perl.org / perl5.git / blobdiff