void
Call_fred()
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_pv("fred", G_DISCARD|G_NOARGS) ;
fprintf(stderr, "back in Call_fred\n") ;
void
Call_fred()
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_pv("fred", G_EVAL|G_DISCARD|G_NOARGS) ;
fprintf(stderr, "back in Call_fred\n") ;
{
dSP ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_pv("PrintUID", G_DISCARD|G_NOARGS) ;
}
=item 1.
-Ignore C<dSP> and C<PUSHMARK(sp)> for now. They will be discussed in
+Ignore C<dSP> and C<PUSHMARK(SP)> for now. They will be discussed in
the next example.
=item 2.
{
dSP ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSVpv(a, 0)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
Parameters are passed to the Perl subroutine using the Perl stack.
This is the purpose of the code beginning with the line C<dSP> and
-ending with the line C<PUTBACK>.
-
+ending with the line C<PUTBACK>. The C<dSP> declares a local copy
+of the stack pointer. This local copy should B<always> be accessed
+as C<SP>.
=item 2.
ENTER ;
SAVETMPS;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(a)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
ENTER ;
SAVETMPS;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(a)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
ENTER ;
SAVETMPS;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(a)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
sva = sv_2mortal(newSViv(a)) ;
svb = sv_2mortal(newSViv(b)) ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sva);
XPUSHs(svb);
PUTBACK ;
ENTER ;
SAVETMPS;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(a)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
CallSubPV(name)
char * name
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_pv(name, G_DISCARD|G_NOARGS) ;
That is fine as far as it goes. The thing is, the Perl subroutine
CallSubSV(name)
SV * name
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_sv(name, G_DISCARD|G_NOARGS) ;
Because we are using an SV to call I<fred> the following can all be used
void
CallSavedSub1()
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_sv(rememberSub, G_DISCARD|G_NOARGS) ;
The reason this is wrong is that by the time you come to use the
void
CallSavedSub2()
CODE:
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
perl_call_sv(keepSub, G_DISCARD|G_NOARGS) ;
To avoid creating a new SV every time C<SaveSub2> is called,
char * method
int index
CODE:
- PUSHMARK(sp);
+ PUSHMARK(SP);
XPUSHs(ref);
XPUSHs(sv_2mortal(newSViv(index))) ;
PUTBACK;
char * class
char * method
CODE:
- PUSHMARK(sp);
+ PUSHMARK(SP);
XPUSHs(sv_2mortal(newSVpv(class, 0))) ;
PUTBACK;
{
dSP ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
/* Call the Perl sub to process the callback */
perl_call_sv(callback, G_DISCARD) ;
if (sv == (SV**)NULL)
croak("Internal error...\n") ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(fh))) ;
XPUSHs(sv_2mortal(newSVpv(buffer, 0))) ;
PUTBACK ;
{
dSP ;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSVpv(buffer, 0))) ;
PUTBACK ;
ENTER ;
SAVETMPS;
- PUSHMARK(sp) ;
+ PUSHMARK(SP) ;
XPUSHs(sv_2mortal(newSViv(a)));
XPUSHs(sv_2mortal(newSViv(b)));
PUTBACK ;
count = perl_call_pv("AddSubtract", G_ARRAY);
SPAGAIN ;
- sp -= count ;
- ax = (sp - stack_base) + 1 ;
+ SP -= count ;
+ ax = (SP - stack_base) + 1 ;
if (count != 2)
croak("Big trouble\n") ;
The code
SPAGAIN ;
- sp -= count ;
- ax = (sp - stack_base) + 1 ;
+ SP -= count ;
+ ax = (SP - stack_base) + 1 ;
sets the stack up so that we can use the C<ST> macro.
invoking an XSUB to preform this operation. Let's see how it can be
done inside our C code:
- SV *perl_eval(char *string, int croak_on_error)
- {
- dSP;
- SV *sv = newSVpv(string,0);
-
- PUSHMARK(sp);
- perl_eval_sv(sv, G_SCALAR);
- SvREFCNT_dec(sv);
-
- SPAGAIN;
- sv = POPs;
- PUTBACK;
-
- if (croak_on_error && SvTRUE(GvSV(errgv)))
- croak(SvPV(GvSV(errgv),na));
-
- return sv;
- }
-
...
- SV *cvrv = perl_eval("sub { print 'You will not find me cluttering any namespace!' }", TRUE);
+ SV *cvrv = perl_eval_pv("sub { print 'You will not find me cluttering any namespace!' }", TRUE);
...
perl_call_sv(cvrv, G_VOID|G_NOARGS);
-L<perl_eval_sv> is used to compile the anonymous subroutine, which can
-then be POPed off the stack. Once this code reference is in hand, it
+L<perlguts/perl_eval_pv> is used to compile the anonymous subroutine, which
+will be the return value as well. Once this code reference is in hand, it
can be mixed in with all the previous examples we've shown.
=head1 SEE ALSO
=head1 DATE
-Version 1.2, 16th Jan 1996
+Version 1.3, 14th Apr 1997