view release on metacpan or  search on metacpan

Data/mkVFunc  view on Meta::CPAN

   elsif (/\b(EXTERN|extern)\b/)
    {
     die "$hfile:$.: $_" unless (/^\s*#\s*define/);
    }
  }
 close(H);


 if (keys %VFunc || keys %VVar)
  {
   my $gard = "\U$hfile";
   $gard =~ s/\..*$//;
   $gard =~ s#/#_#g;
   my $name = "\u\L${gard}\UV";
   $fdef = $hfile;
   $fdef =~ s/\..*$/.t/;
   $mdef = $hfile;
   $mdef =~ s/\..*$/.m/;

   my $htfile = $hfile;
   $htfile =~ s/\..*$/_f.h/;
   unless (-r $htfile)
    {
     open(C,">$htfile") || die "Cannot open $htfile:$!";
     print C "#ifndef ${gard}_VT\n";
     print C "#define ${gard}_VT\n";
     print C "#include \"$hfile\"\n";
     print C "typedef struct ${name}tab\n{\n";
     print C "#define VFUNC(type,name,mem,args) type (*mem) args;\n";
     print C "#define VVAR(type,name,mem)       type (*mem);\n";
     print C "#include \"$fdef\"\n";
     print C "#undef VFUNC\n";
     print C "#undef VVAR\n";
     print C "} ${name}tab;\n";
     print C "extern ${name}tab *${name}ptr;\n";
     print C "extern ${name}tab *${name}Get _((void));\n";
     print C "#endif /* ${gard}_VT */\n";
     close(C);
    }

   my $cfile = $hfile;
   $cfile =~ s/\..*$/_f.c/;
   unless (-r $cfile)
    {
     open(C,">$cfile") || die "Cannot open $cfile:$!";
     print C "#include \"$hfile\"\n";
     print C "#include \"$htfile\"\n";
     print C "static ${name}tab ${name}table =\n{\n";
     print C "#define VFUNC(type,name,mem,args) name,\n";
     print C "#define VVAR(type,name,mem)      &name,\n";
     print C "#include \"$fdef\"\n";
     print C "#undef VFUNC\n";
     print C "#undef VVAR\n";
     print C "};\n";
     print C "${name}tab *${name}ptr;\n";
     print C "${name}tab *${name}Get() { return ${name}ptr = &${name}table;}\n";
     close(C);
    }

   print STDERR "$gard\n";
   chmod(0666,$fdef) unless -w $fdef;
   open(VFUNC,">$fdef")   || die "Cannot open $fdef:$!";
   chmod(0666,$mdef) unless -w $mdef;
   open(VMACRO,">$mdef")  || die "Cannot open $mdef:$!";
   print VFUNC  "#ifdef _$gard\n";
   print VMACRO "#ifndef _${gard}_VM\n";
   print VMACRO "#define _${gard}_VM\n";
   print VMACRO "#include \"$htfile\"\n";
   foreach $func (sort keys %VVar)
    {
     if (!exists $Exclude{$func})
      {
       print VFUNC $VVar{$func};
       print VMACRO "#define $func (*${name}ptr->V_$func)\n"
      }
    }
   foreach $func (sort keys %VFunc)
    {
     if (!exists $Exclude{$func})
      {
       print VFUNC $VFunc{$func};
       print VMACRO "#define $func (*${name}ptr->V_$func)\n"
      }
    }
   print VMACRO "#endif /* _${gard}_VM */\n";
   close(VMACRO);
   print VFUNC  "#endif /* _$gard */\n";
   close(VFUNC); # Close this last - Makefile dependancy
  }
}

foreach (<tk*Tab.c>)
 {
  Exclude($_);
 }

foreach (@ARGV)
 {
  Vfunc($_);
 }

__END__

=head1 NAME

mkVFunc - Support for "nested" dynamic loading

=head1 SYNOPSIS

 mkVFunc xxx.h

=head1 DESCRIPTION

B<perl/Tk> is designed so that B<Tk> can be dynamically loaded 'on top of'
perl. That is the easy bit. What it also does is allow Tk::Xxxx to be
dynamically loaded 'on top of' the B<perl/Tk> composite. Thus when
you 'require Tk::HList' the shared object F<.../HList.so> needs to be
able to call functions defined in perl I<and> functions defined in loadable
.../Tk.so . Now functions in 'base executable' are a well known problem,
and are solved by DynaLoader. However most of dynamic loading schemes
cannot handle one loadable calling another loadable.

Thus what Tk does is build a table of functions that should be callable.