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Diffstat (limited to 'pod/perlxs.pod')
| -rw-r--r-- | pod/perlxs.pod | 279 |
1 files changed, 70 insertions, 209 deletions
diff --git a/pod/perlxs.pod b/pod/perlxs.pod index df2aefa0b6..b663dcfa2d 100644 --- a/pod/perlxs.pod +++ b/pod/perlxs.pod @@ -23,38 +23,7 @@ many common C types. A supplement typemap must be created to handle special structures and types for the library being linked. -=head2 Getting Started - -A new extension should begin with the B<h2xs> tool. This will generate -templates for the new Perl module (PM), the XS source file (XS), the MANIFEST -file, and the Makefile.PL (PL) files. The Makefile.PL file is a Perl script -which will generate a Makefile. This makefile knows how to find and run -xsubpp for your extension. When you type "make" your XS file will be run -through xsubpp and a C file will be produced. Then the C file will be -compiled. A simple example looks like this for an example module named -B<Foo>: - - $ h2xs -Afn Foo - $ cd ext/Foo - $ ls - Foo.pm Foo.xs MANIFEST Makefile.PL - $ perl5 Makefile.PL - $ ls - Foo.pm Foo.xs MANIFEST Makefile.PL Makefile - $ <edit Foo.pm and Foo.xs to add your stuff> - $ make - <you will see xsubpp run on Foo.xs and you'll see the C compiler - <run on Foo.c, and a bunch of other less-interesting things - <will happen. - -If your Perl was built with dynamic loading then the makefile will build a -dynamically loadable extension. If you don't have dynamic loading then the -makefile will build a static extension and should create a new Perl binary. -The default behavior depends on what is available. - -For more information about h2xs consult its manpage, embedded in the -source. For information about the Makefile.PL and Makefile consult the -MakeMaker manpage. +See L<perlxstut> for a tutorial on the whole extension creation process. =head2 On The Road @@ -451,8 +420,8 @@ Perl as a single list. bool_t status; status = rpcb_gettime( host, &timep ); EXTEND(sp, 2); - PUSHs(sv_2mortal(newSVnv(status))); - PUSHs(sv_2mortal(newSVnv(timep))); + PUSHs(sv_2mortal(newSViv(status))); + PUSHs(sv_2mortal(newSViv(timep))); } Notice that the programmer must supply the C code necessary @@ -535,7 +504,7 @@ then not push return values on the stack. { time_t timep; if( rpcb_gettime( host, &timep ) ) - PUSHs(sv_2mortal(newSVnv(timep))); + PUSHs(sv_2mortal(newSViv(timep))); else{ /* Nothing pushed on stack, so an empty */ /* list is implicitly returned. */ @@ -592,92 +561,89 @@ If a function is defined as a C++ method then it will assume its first argument is an object pointer. The object pointer will be stored in a variable called THIS. The object should have been created by C++ with the new() function and should -be blessed by Perl with the sv_setptrobj() macro. The -blessing of the object by Perl can be handled by the -T_PTROBJ typemap. +be blessed by Perl with the sv_setref_pv() macro. The +blessing of the object by Perl can be handled by a typemap. An example +typemap is shown at the end of this section. If the method is defined as static it will call the C++ function using the class::method() syntax. If the method is not static the function will be called using the THIS->method() syntax. -=head2 Perl Variables +The next examples will use the following C++ class. -The following demonstrates how the Perl variable $host can -be accessed from an XSUB. The function B<perl_get_sv()> is -used to obtain a pointer to the variable, known as an B<SV> -(Scalar Variable) internally. The package name C<RPC> will be -added to the name of the variable so perl_get_sv() will know -in which package $host can be found. If the package name is -not supplied then perl_get_sv() will search package C<main> for -the variable. The macro B<SvPVX()> is then used to dereference -the SV to obtain a C<char*> pointer to its contents. + class colors { + public: + colors(); + ~colors(); + int blue(); + void set_blue( int ); + + private: + int c_blue; + }; + +The XSUBs for the blue() and set_blue() methods are defined with the class +name but the parameter for the object (THIS, or "self") is implicit and is +not listed. + + int + color::blue() void - rpcb_gettime() - PPCODE: - { - char *host; - SV *hostsv; - time_t timep; - - hostsv = perl_get_sv( "RPC::host", FALSE ); - if( hostsv != NULL ){ - host = SvPVX( hostsv ); - if( rpcb_gettime( host, &timep ) ) - PUSHs(sv_2mortal(newSVnv(timep))); - } - } + color::set_blue( val ) + int val -This Perl code can be used to call that XSUB. +Both functions will expect an object as the first parameter. The xsubpp +compiler will call that object C<THIS> and will use it to call the specified +method. So in the C++ code the blue() and set_blue() methods will be called +in the following manner. - $RPC::host = "localhost"; - $timep = rpcb_gettime(); + RETVAL = THIS->blue(); -In the above example the SV contained a C C<char*> but a Perl -scalar variable may also contain numbers and references. If -the SV is expected to have a C C<int> then the macro B<SvIVX()> -should be used to dereference the SV. When the SV contains -a C double then B<SvNVX()> should be used. + THIS->set_blue( val ); -The macro B<SvRV()> can be used to dereference an SV when it is a Perl -reference. The result will be another SV which points to the actual Perl -variable. This can then be dereferenced with SvPVX(), SvNVX(), or -SvIVX(). The following XSUB will use SvRV(). +If the function's name is B<DESTROY> then the C++ C<delete> function will be +called and C<THIS> will be given as its parameter. void - rpcb_gettime() - PPCODE: - { - char *host; - SV *rv; - SV *hostsv; - time_t timep; - - rv = perl_get_sv( "RPC::host", FALSE ); - if( rv != NULL ){ - hostsv = SvRV( rv ); - host = SvPVX( hostsv ); - if( rpcb_gettime( host, &timep ) ) - PUSHs(sv_2mortal(newSVnv(timep))); - } - } + color::DESTROY() + +The C++ code will call C<delete>. + + delete THIS; -This Perl code will create a variable $RPC::host which is a -reference to $MY::host. The variable $MY::host contains the -hostname which will be used. +If the function's name is B<new> then the C++ C<new> function will be called +to create a dynamic C++ object. The XSUB will expect the class name, which +will be kept in a variable called C<CLASS>, to be given as the first +argument. - $MY::host = "localhost"; - $RPC::host = \$MY::host; - $timep = rpcb_gettime(); + color * + color::new() -The second argument to perl_get_sv() will normally be B<FALSE> -as shown in the above examples. An argument of B<TRUE> will -cause variables to be created if they do not already exist. -One should not use TRUE unless steps are taken to deal with -a possibly empty SV. +The C++ code will call C<new>. -XSUBs may use B<perl_get_av()>, B<perl_get_hv()>, and B<perl_get_cv()> to -access Perl arrays, hashes, and code values. + RETVAL = new color(); + +The following is an example of a typemap that could be used for this C++ +example. + + TYPEMAP + color * O_OBJECT + + OUTPUT + # The Perl object is blessed into 'CLASS', which should be a + # char* having the name of the package for the blessing. + O_OBJECT + sv_setref_pv( $arg, CLASS, (void*)$var ); + + INPUT + O_OBJECT + if( sv_isobject($arg) && (SvTYPE(SvRV($arg)) == SVt_PVMG) ) + $var = ($type)SvIV((SV*)SvRV( $arg )); + else{ + warn( \"${Package}::$func_name() -- $var is not a blessed SV reference\" ); + XSRETURN_UNDEF; + } =head2 Interface Strategy @@ -707,41 +673,6 @@ cases it may be helpful to use the T_PTROBJ typemap for these structures so they can be manipulated by Perl as blessed objects. -=head2 The Perl Module - -The Perl module is the link between the extension library, -which was generated from XS code, and the Perl interpreter. -The module is used to tell Perl what the extension library -contains. The name and package of the module should match -the name of the library. - -The following is a Perl module for an extension containing -some ONC+ RPC bind library functions. - - package RPC; - - require Exporter; - require DynaLoader; - @ISA = qw(Exporter DynaLoader); - @EXPORT = qw( rpcb_gettime rpcb_getmaps rpcb_getaddr - rpcb_rmtcall rpcb_set rpcb_unset ); - - bootstrap RPC; - 1; - -The RPC extension contains the functions found in the -@EXPORT list. By using the C<Exporter> module the RPC module -can make these function names visible to the rest of the -Perl program. The C<DynaLoader> module will allow the RPC -module to bootstrap the extension library. To load this -extension and make the functions available, the following -Perl statement should be used. - - use RPC; - -For more information about the DynaLoader consult its documentation in the -ext/DynaLoader directory in the Perl source. - =head2 Perl Objects And C Structures When dealing with C structures one should select either @@ -808,76 +739,6 @@ does not care, that this object is a C struct and not a Perl object. In this sense, there is no difference between the object created by the getnetconfigent() XSUB and an object created by a normal Perl subroutine. -=head2 C Headers and Perl - -The B<h2xs> compiler is designed to convert C header files in -/usr/include into Perl extensions. This compiler will -create a directory under the C<ext> directory of the Perl -source and will populate it with a Makefile, a Perl Module, -an XS source file, and a MANIFEST file. - -The following command will create an extension called C<Rusers> -from the <rpcsvc/rusers.h> header. - - h2xs rpcsvc/rusers - -When the Rusers extension has been compiled and installed -Perl can use it to retrieve any C<#define> statements which -were in the C header. - - use Rusers; - print "RPC program number for rusers service: "; - print &RUSERSPROG, "\n"; - -=head2 Creating A New Extension - -The B<h2xs> compiler can generate template source files and -Makefiles. These templates offer a suitable starting point -for most extensions. The following example demonstrates how -one might use B<h2xs> to create an extension containing the RPC -functions in this document. - -The extension will not use autoloaded functions and will not define -constants, so the B<-A> option will be given to B<h2xs>. When run from the -Perl source directory, the B<h2xs> compiler will create the directory -ext/RPC and will populate it with files called RPC.xs, RPC.pm, Makefile.PL, -and MANIFEST. The XS code for the RPC functions should be added to the -RPC.xs file. The @EXPORT list in RPC.pm should be updated to include the -functions from RPC.xs. - - h2xs -An RPC - -To compile the extension for dynamic loading the following -command should be executed from the ext/RPC directory. - - make dynamic - -If the extension will be statically linked into the Perl -binary then the makefile (use C<makefile>, not C<Makefile>) in the -Perl source directory should be edited to add C<ext/RPC/RPC.a> -to the C<static_ext> variable. Before making this change Perl -should have already been built. After the makefile has been -updated the following command should be executed from the -Perl source directory. - - make - -Perl's B<Configure> script can also be used to add extensions. The extension -should be placed in the C<ext> directory under the Perl source before Perl -has been built and prior to running Configure. When Configure is run it -will find the extension along with the other extensions in the C<ext> -directory and will add it to the list of extensions to be built. When make -is run the extension will be built along with the other extensions. - -Configure recognizes extensions if they have an XS source -file which matches the name of the extension directory. If -the extension directory includes a MANIFEST file Configure -will search that file for any B<.SH> files and extract them -after it extracts all the other .SH files listed in the main -MANIFEST. The main Perl Makefile will then run B<make> in the -extension's directory if it finds an XS file matching the -name of the extension's directory. - =head2 The Typemap The typemap is a collection of code fragments which are used by the B<xsubpp> @@ -982,4 +843,4 @@ File C<rpctest.pl>: Perl test program for the RPC extension. =head1 AUTHOR Dean Roehrich F<E<lt>roehrich@cray.comE<gt>> -Oct 12, 1995 +Dec 10, 1995 |