Remove some of the auto declarations in response to review comments

Will remove the rest in a follow-up commit.

Author: michaelbautin

examples/cpp/example_epsilon_search.cpp

@@ -53,7 +53,8 @@ int main() {
         }
         std::cout << "Query #" << i << "\n";
         hnswlib::EpsilonSearchStopCondition<dist_t> stop_condition(epsilon2, min_num_candidates, max_elements);
-        auto result = alg_hnsw->searchStopConditionClosest(query_data, stop_condition);
+        std::vector<std::pair<float, hnswlib::labeltype>> result =
+            alg_hnsw->searchStopConditionClosest(query_data, stop_condition);
         size_t num_vectors = result.size();
         std::cout << "Found " << num_vectors << " vectors\n";
         delete[] query_data;

examples/cpp/example_filter.cpp

@@ -45,7 +45,8 @@ int main() {
     // Query the elements for themselves with filter and check returned labels
     int k = 10;
     for (int i = 0; i < max_elements; i++) {
-        auto result = alg_hnsw->searchKnnCloserFirst(data + i * dim, k, &pickIdsDivisibleByTwo);
+        std::vector<std::pair<float, hnswlib::labeltype>> result =
+            alg_hnsw->searchKnnCloserFirst(data + i * dim, k, &pickIdsDivisibleByTwo);
         for (auto item: result) {
             if (item.second % 2 == 1) std::cout << "Error: found odd label\n";
         }

examples/cpp/example_multivector_search.cpp

@@ -63,7 +63,8 @@ int main() {
         }
         std::cout << "Query #" << i << "\n";
         hnswlib::MultiVectorSearchStopCondition<docidtype, dist_t> stop_condition(space, num_docs, ef_collection);
-        auto result = alg_hnsw->searchStopConditionClosest(query_data, stop_condition);
+        std::vector<std::pair<float, hnswlib::labeltype>> result =
+            alg_hnsw->searchStopConditionClosest(query_data, stop_condition);
         size_t num_vectors = result.size();
 
         std::unordered_map<docidtype, size_t> doc_counter;

hnswlib/hnswlib.h

@@ -146,13 +146,13 @@ class [[nodiscard]] Status {
     Status(const char* message) : message_(message) {}
 
     // Returns true if the status is OK
-    bool ok() const { return message_ == nullptr; }
+    bool ok() const { return !message_; }
 
     // Returns the error message, or nullptr if OK
     const char* message() const { return message_; }
 
 private:
-    // Null if OK, a message otherwise.
+    // nullptr if OK, a message otherwise.
     const char* message_;
 };
 

tests/cpp/epsilon_search_test.cpp

@@ -94,7 +94,7 @@ int main() {
     int min_candidates_small = 500;
     for (size_t i = 0; i < max_elements; i++) {
         hnswlib::EpsilonSearchStopCondition<dist_t> stop_condition(epsilon2_small, min_candidates_small, max_num_candidates);
-        auto result =
+        std::vector<std::pair<float, hnswlib::labeltype>> result =
             alg_hnsw->searchStopConditionClosest(alg_hnsw->getDataByInternalId(i), stop_condition);
         size_t num_vectors = result.size();
         // get closest distance

tests/cpp/multiThreadLoad_test.cpp

@@ -115,7 +115,7 @@ int main() {
                             data[i] = distrib_real(rng);
                         }
                         alg_hnsw->addPoint(data.data(), label);
-                        auto data = alg_hnsw->getDataByLabel<float>(label);
+                        std::vector<float> data = alg_hnsw->getDataByLabel<float>(label);
                         float max_val = *max_element(data.begin(), data.end());
                         // never happens but prevents compiler from deleting unused code
                         if (max_val > 10) {

tests/cpp/updates_test.cpp

@@ -111,7 +111,7 @@ test_approx(std::vector<float> &queries, size_t qsize, hnswlib::HierarchicalNSW<
     size_t total = 0;
 
     for (int i = 0; i < qsize; i++) {
-        auto result = appr_alg.searchKnn((char *)(queries.data() + vecdim * i), K);
+        std::priority_queue<std::pair<d_type, hnswlib::labeltype>> result = appr_alg.searchKnn((char *)(queries.data() + vecdim * i), K);
         total += K;
         while (result.size()) {
             if (answers[i].find(result.top().second) != answers[i].end()) {