--- a/src/parallel_execution/SingleLinkedStack.cbc	Sat Jan 28 12:37:22 2017 +0900
+++ b/src/parallel_execution/SingleLinkedStack.cbc	Sat Jan 28 15:46:33 2017 +0900
@@ -94,7 +94,7 @@
         }
     } else {
         data = NULL;
-        data1 = NUll;
+        data1 = NULL;
     }
     goto next(data, data1, ...);
 }

--- a/src/parallel_execution/generate_stub.pl	Sat Jan 28 12:37:22 2017 +0900
+++ b/src/parallel_execution/generate_stub.pl	Sat Jan 28 15:46:33 2017 +0900
@@ -34,6 +34,8 @@
 my %var;
 my %code;
 my %dataGearVar;
+my %outputVar;       # output var initializer
+my %outputArgs;      # continuation's output variables
 my %dataGear;
 my %dataGearName;
 my $implementation;
@@ -85,24 +87,39 @@
 }
 
 sub generateStubArgs {
-    my($codeGearName, $varName, $typeName, $typeField, $interface) = @_;
-    push @{$dataGearVar{$codeGearName}},$varName; 
-    if ($typeField ne $varName) {
+    my($codeGearName, $varName, $typeName, $typeField, $interface,$output) = @_;
+    my $varname1 = $output?"O_$varName":$varName; 
+    for my $n ( @{$dataGearVar{$codeGearName}} ) {
+        # we already have it
+        return 0 if ( $n eq $varname1);
+    }
+    push @{$dataGearVar{$codeGearName}}, $varname1;
+    if ($typeName eq $implementation) {
+        # get implementation
         $dataGearName{$codeGearName} .= "\t$typeName* $varName = ($typeName*)GearImpl(context, $interface, $varName);\n";
     } else {
         for my $ivar (keys %{$var{$interface}}) {
+            #  input data gear field 
             if ($varName eq $ivar) {
+                if ($output) {
+                    $dataGearName{$codeGearName} .= "\t$typeName** O_$varName = &Gearef(context, $interface)->$varName;\n";
+                    $outputVar{$codeGearName} .= "\t$typeName* $varName;\n";
+                    return 1;
+                }
                 $dataGearName{$codeGearName} .= "\t$typeName* $varName = Gearef(context, $interface)->$varName;\n";
-                return;
+                return 1;
             }
         }
         for my $cName (keys %{$code{$interface}}) {
             if ($varName eq $cName) {
+                # continuation field
                 $dataGearName{$codeGearName} .= "\tenum Code $varName = Gearef(context, $interface)->$varName;\n";
-                return;
+                return 1;
             }
         }
+        # global variable case
         $dataGearName{$codeGearName} .= "\t$typeName* $varName = Gearef(context, $typeName)->$typeField;\n";
+        return 1;
     }
 }
 
@@ -158,33 +175,40 @@
                 }
                 $prevCodeGearName = $codeGearName;
                 $dataGearVar{$codeGearName} = [];
+                $outputVar{$codeGearName} = "";
+                $outputArgs{$codeGearName} = {};
                 my $newArgs = "struct Context *context,";
                 while($args) {
                     if ($args =~ s/(^\s*,\s*)//) {
                         $newArgs .= $1;
                     }
                     # replace __code next
-                    if ($args =~ s/^\_\_code\s(\w+)\([^)]*\)//) {
+                    if ($args =~ s/^\_\_code\s+(\w+)\(([^)]*)\)//) {
                         my $next = $1;
                         my @args = split(/,/,$2);
-                        $newArgs .= "enum Code $next";
+                        if ( &generateStubArgs($codeGearName, $next, "Code", $next, $interface,0) ) {
+                            $newArgs .= "enum Code $next";
+                        }
                         for my $arg (@args) {
                             $arg =~ s/^\s*//;
+                            last if ($arg =~ /\.\.\./);
                             $arg =~ s/^(struct|union) (\w+)(\*)+\s(\w+)//;
                             my $structType = $1;
                             my $typeName = $2;
                             my $varName = $4;
                             my $typeField = lcfirst($typeName);
-                            &generateStubArgs($codeGearName, $varName, $typeName, $typeField, $interface);
+                            push(@{$outputArgs{$codeGearName}->{$next}}, $varName);
+                            if (&generateStubArgs($codeGearName, $varName, $typeName, $typeField, $interface,1)) {
+                                $newArgs .= ",$structType $typeName **O_$varName";
+                            }
                         }
-                        &generateStubArgs($codeGearName, $next, "Code", $next, $interface);
                     } elsif ($args =~ s/^(struct|union) (\w+)(\*)+\s(\w+)//) {
                         my $structType = $1;
                         my $typeName = $2;
                         my $varName = $4;
                         my $typeField = lcfirst($typeName);
-                        $newArgs .= $&;
-                        &generateStubArgs($codeGearName, $varName, $typeName, $typeField, $interface);
+                        $newArgs .= $&;    # assuming no duplicate
+                        &generateStubArgs($codeGearName, $varName, $typeName, $typeField, $interface,0);
                     } elsif ($args =~ s/(.*,)//) {
                         $newArgs .= $1; 
                     } else {
@@ -198,11 +222,21 @@
                 }
                 $dataGearName{$codeGearName} .= ");";
                 print $fd "__code $codeGearName($newArgs)$tail\n";
+                if ($outputVar{$codeGearName} ne "") {
+                    print $fd $outputVar{$codeGearName};
+                }
                 next;
-            } elsif (/^(.*)goto next\(\.\.\.(.*)\);/) {
+            } elsif (/^(.*)goto (\w+)\((.*)\);/) {
                 my $prev = $1;
-                my $args = $2;
-                print $fd "${prev}goto meta(context, next);\n";
+                my $next = $2;
+                my @args = split(/,/,$3);
+                # write continuation's arguments
+                # we may need a commit for a shared DataGear
+                for my $arg ( @{$outputArgs{$codeGearName}->{$next}} ) {
+                    my $v = shift(@args);
+                    print $fd "\t*O_$arg = $v;\n";
+                }
+                print $fd "${prev}goto meta(context, $next);\n";
                 next;
             } else {
                 s/new\s+(\w+)\(\)/\&ALLOCATE(context, \1)->\1/g;   # replacing new

--- a/src/parallel_execution/worker.c	Sat Jan 28 12:37:22 2017 +0900
+++ b/src/parallel_execution/worker.c	Sat Jan 28 15:46:33 2017 +0900
@@ -47,7 +47,7 @@
 
 __code getTask_stub(struct Context* context) {
     Worker* worker = &Gearef(context,Worker)->worker->Worker;
-    struct Context* task = &Gearef(context, Queue)->data->context;
+    struct Context* task = &Gearef(context, Queue)->data->Context;
     goto getTask(context, worker, task);
 }