[win32] the EXTCONST in sdbm.h breaks SDBM on Borland, since

[p5sagit/p5-mst-13.2.git] / pod / perlxs.pod

diff --git a/pod/perlxs.pod b/pod/perlxs.pod
index 13ad669..d065b94 100644 (file)
--- a/pod/perlxs.pod
+++ b/pod/perlxs.pod
@@ -277,6 +277,17 @@ typemap.
           OUTPUT:
           timep sv_setnv(ST(1), (double)timep);
 
+B<xsubpp> emits an automatic C<SvSETMAGIC()> for all parameters in the
+OUTPUT section of the XSUB, except RETVAL.  This is the usually desired
+behavior, as it takes care of properly invoking 'set' magic on output
+parameters (needed for hash or array element parameters that must be
+created if they didn't exist).  If for some reason, this behavior is
+not desired, the OUTPUT section may contain a C<SETMAGIC: DISABLE> line
+to disable it for the remainder of the parameters in the OUTPUT section.
+Likewise,  C<SETMAGIC: ENABLE> can be used to reenable it for the
+remainder of the OUTPUT section.  See L<perlguts> for more details
+about 'set' magic.
+
 =head2 The CODE: Keyword
 
 This keyword is used in more complicated XSUBs which require
@@ -547,7 +558,7 @@ Perl as a single list.
           bool_t  status;
           PPCODE:
           status = rpcb_gettime( host, &timep );
-          EXTEND(sp, 2);
+          EXTEND(SP, 2);
           PUSHs(sv_2mortal(newSViv(status)));
           PUSHs(sv_2mortal(newSViv(timep)));
 
@@ -562,7 +573,7 @@ directive.
 
 The EXTEND() macro is used to make room on the argument
 stack for 2 return values.  The PPCODE: directive causes the
-B<xsubpp> compiler to create a stack pointer called C<sp>, and it
+B<xsubpp> compiler to create a stack pointer available as C<SP>, and it
 is this pointer which is being used in the EXTEND() macro.
 The values are then pushed onto the stack with the PUSHs()
 macro.
@@ -572,6 +583,9 @@ the following statement.
 
      ($status, $timep) = rpcb_gettime("localhost");
 
+When handling output parameters with a PPCODE section, be sure to handle
+'set' magic properly.  See L<perlguts> for details about 'set' magic.
+
 =head2 Returning Undef And Empty Lists
 
 Occasionally the programmer will want to return simply
@@ -1102,6 +1116,37 @@ that the C unary operator C<*> is considered to be a part of the C type name.
      TYPEMAP
      Netconfig *<tab>T_PTROBJ
 
+Here's a more complicated example: suppose that you wanted C<struct
+netconfig> to be blessed into the class C<Net::Config>.  One way to do
+this is to use underscores (_) to separate package names, as follows:
+
+        typedef struct netconfig * Net_Config;
+
+And then provide a typemap entry C<T_PTROBJ_SPECIAL> that maps underscores to
+double-colons (::), and declare C<Net_Config> to be of that type:
+
+
+        TYPEMAP
+        Net_Config      T_PTROBJ_SPECIAL
+
+        INPUT
+        T_PTROBJ_SPECIAL
+                if (sv_derived_from($arg, \"${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")) {
+                        IV tmp = SvIV((SV*)SvRV($arg));
+                $var = ($type) tmp;
+                }
+                else
+                        croak(\"$var is not of type ${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")
+
+        OUTPUT
+        T_PTROBJ_SPECIAL
+                sv_setref_pv($arg, \"${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\",
+                (void*)$var);
+
+The INPUT and OUTPUT sections substitute underscores for double-colons
+on the fly, giving the desired effect.  This example demonstrates some
+of the power and versatility of the typemap facility.
+
 =head1 EXAMPLES
 
 File C<RPC.xs>: Interface to some ONC+ RPC bind library functions.