Listing 4.22 - does not compile

listings/listing_4.22.cpp

@@ -1,16 +1,18 @@
 #include <future>
-std::future<FinalResult> process_data(std::vector<MyData>& vec)
+std::future<FinalResult> process_data(const std::vector<MyData>& vec)
 {
     size_t const chunk_size=whatever;
+    size_t remaining_size, this_chunk_size;
     std::vector<std::future<ChunkResult>> results;
-    for(auto begin=vec.begin(),end=vec.end();beg!=end;){
-        size_t const remaining_size=end-begin;
-        size_t const this_chunk_size=std::min(remaining_size,chunk_size);
-        results.push_back(
-            std::async(process_chunk,begin,begin+this_chunk_size));
-        begin+=this_chunk_size;
+    for(auto it=vec.begin(),end=vec.end();it!=end;){
+        remaining_size=end-it;
+        this_chunk_size=std::min(remaining_size,chunk_size);
+        results.push_back(std::async([=] () {
+            return process_chunk_template(it,it+this_chunk_size);
+        }));
+        it+=this_chunk_size;
     }
-    return std::async([all_results=std::move(results)](){
+    return std::async([all_results=std::move(results)] () mutable {
         std::vector<ChunkResult> v;
         v.reserve(all_results.size());
         for(auto& f: all_results)