Note: For some extensions, Dave Beazley's SWIG system may provide a
significantly more convenient mechanism for creating the extension
-glue code. See http://www.swig.org/ for more information.
+glue code. See L<http://www.swig.org/> for more information.
=head2 On The Road
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).
UNDEF. If you do not set any FALLBACK value when using OVERLOAD,
it defaults to UNDEF. FALLBACK is not used except when one or
more functions using OVERLOAD have been defined. Please see
-L<overload/Fallback> for more details.
+L<overload/fallback> for more details.
=head2 The INTERFACE: Keyword
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 )
INCLUDE: Rpcb1.xsh
If the parameters to the INCLUDE: keyword are followed by a pipe (C<|>) then
-the compiler will interpret the parameters as a command.
+the compiler will interpret the parameters as a command. This feature is
+mildly deprecated in favour of the C<INCLUDE_COMMAND:> directive, as documented
+below.
INCLUDE: cat Rpcb1.xsh |
+Do not use this to run perl: C<INCLUDE: perl |> will run the perl that
+happens to be the first in your path and not necessarily the same perl that is
+used to run C<xsubpp>. See L<"The INCLUDE_COMMAND: Keyword">.
+
+=head2 The INCLUDE_COMMAND: Keyword
+
+Runs the supplied command and includes its output into the current XS
+document. C<INCLUDE_COMMAND> assigns special meaning to the C<$^X> token
+in that it runs the same perl interpreter that is running C<xsubpp>:
+
+ INCLUDE_COMMAND: cat Rpcb1.xsh
+
+ INCLUDE_COMMAND: $^X -e ...
+
=head2 The CASE: Keyword
The CASE: keyword allows an XSUB to have multiple distinct parts with each
The section labels C<TYPEMAP>, C<INPUT>, or C<OUTPUT> must begin
in the first column on a line by themselves, and must be in uppercase.
-The default typemap in the C<lib/ExtUtils> directory of the Perl source
+The default typemap in the F<lib/ExtUtils> directory of the Perl source
contains many useful types which can be used by Perl extensions. Some
extensions define additional typemaps which they keep in their own directory.
These additional typemaps may reference INPUT and OUTPUT maps in the main
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>
=item typedef my_cxt_t
-This struct typedef I<must> always be called C<my_cxt_t> -- the other
+This struct typedef I<must> always be called C<my_cxt_t>. The other
C<CXT*> macros assume the existence of the C<my_cxt_t> typedef name.
Declare a typedef named C<my_cxt_t> that is a structure that contains
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 L<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