use std::atomic<bool> in external boolean for time limit

examples/cpp/sat_runner.cc

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <atomic>
 #include <cstdio>
 #include <cstdlib>
 #include <memory>
@@ -219,7 +220,7 @@ int Run() {
   // completely replaced by the more general CpModelProto.
   if (!cp_model.variables().empty()) {
     problem.Clear();  // We no longer need it, release memory.
-    bool stopped = false;
+    std::atomic<bool> stopped(false);
     Model model;
     model.Add(NewSatParameters(parameters));
     model.GetOrCreate<TimeLimit>()->RegisterExternalBooleanAsLimit(&stopped);

ortools/flatzinc/cp_model_fz_solver.cc

@@ -13,6 +13,7 @@
 
 #include "ortools/flatzinc/cp_model_fz_solver.h"
 
+#include <atomic>
 #include <cmath>
 #include <limits>
 #include <unordered_map>
@@ -923,7 +924,7 @@ void SolveFzWithCpModelProto(const fz::Model& fz_model,
       << sat_params;
   m.parameters.MergeFrom(flag_parameters);
 
-  bool stopped = false;
+  std::atomic<bool> stopped(false);
   SigintHandler handler;
   handler.Register([&stopped]() { stopped = true; });
 

ortools/linear_solver/bop_interface.cc

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <atomic>
 #include <fstream>
 #include <string>
 #include <vector>
@@ -115,7 +116,7 @@ class BopInterface : public MPSolverInterface {
   std::vector<MPSolver::BasisStatus> row_status_;
   bop::BopParameters parameters_;
   double best_objective_bound_;
-  bool interrupt_solver_;
+  std::atomic<bool> interrupt_solver_;
 };
 
 BopInterface::BopInterface(MPSolver* const solver)

ortools/linear_solver/glop_interface.cc

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <atomic>
 #include <fstream>
 #include <string>
 #include <unordered_map>
@@ -102,7 +103,7 @@ class GLOPInterface : public MPSolverInterface {
   std::vector<MPSolver::BasisStatus> column_status_;
   std::vector<MPSolver::BasisStatus> row_status_;
   glop::GlopParameters parameters_;
-  bool interrupt_solver_;
+  std::atomic<bool> interrupt_solver_;
 };
 
 GLOPInterface::GLOPInterface(MPSolver* const solver)

ortools/sat/cp_model_solver.cc

@@ -3019,10 +3019,10 @@ CpSolverResponse SolveCpModelParallel(
   const SatParameters& params = *model->GetOrCreate<SatParameters>();
   CHECK(!params.enumerate_all_solutions());
 
-  // This is a bit hacky. If the provided TimeLimit as a "stopped" Boolean, we
+  // This is a bit hacky. If the provided TimeLimit as a "`" Boolean, we
   // use this one instead.
-  bool stopped_boolean = false;
-  bool* stopped = &stopped_boolean;
+  std::atomic<bool> stopped_boolean(false);
+  std::atomic<bool>* stopped = &stopped_boolean;
   if (model->GetOrCreate<TimeLimit>()->ExternalBooleanAsLimit() != nullptr) {
     stopped = model->GetOrCreate<TimeLimit>()->ExternalBooleanAsLimit();
   }
@@ -3045,11 +3045,10 @@ CpSolverResponse SolveCpModelParallel(
   auto fix_walltime = ::operations_research::util::MakeCleanup(
       [&timer, &best_response]() { best_response.set_wall_time(timer.Get()); });
 
-  // In the LNS threads, we wait for this notification before starting work.
-  absl::Notification first_solution_found_or_search_finished;
-
   absl::Mutex mutex;
   const int num_search_workers = params.num_search_workers();
+  // In the LNS threads, we wait for this notification before starting work.
+  absl::Notification first_solution_found_or_search_finished;
   VLOG(1) << "Starting parallel search with " << num_search_workers
           << " workers.";
   ThreadPool pool("Parallel_search", num_search_workers);
@@ -3294,10 +3293,6 @@ CpSolverResponse SolveCpModel(const CpModelProto& model_proto, Model* model) {
         }
       };
 
-#if defined(__PORTABLE_PLATFORM__)
-  model->GetOrCreate<SatParameters>()->set_num_search_workers(1);
-#endif  // __PORTABLE_PLATFORM__
-
   CpSolverResponse response;
   if (params.num_search_workers() > 1) {
 #if !defined(__PORTABLE_PLATFORM__)

ortools/util/time_limit.h

@@ -15,6 +15,7 @@
 #define OR_TOOLS_UTIL_TIME_LIMIT_H_
 
 #include <algorithm>
+#include <atomic>
 #include <cstdlib>
 #include <limits>
 #include <memory>
@@ -240,12 +241,15 @@ class TimeLimit {
   // the check of the limit.
   //
   // Note that ResetLimitFromParameters() will set this Boolean to false.
-  void RegisterExternalBooleanAsLimit(bool* external_boolean_as_limit) {
+  void RegisterExternalBooleanAsLimit(
+      std::atomic<bool>* external_boolean_as_limit) {
     external_boolean_as_limit_ = external_boolean_as_limit;
   }
 
   // Returns the current external Boolean limit.
-  bool* ExternalBooleanAsLimit() const { return external_boolean_as_limit_; }
+  std::atomic<bool>* ExternalBooleanAsLimit() const {
+    return external_boolean_as_limit_;
+  }
 
   // Sets new time limits. Note that this do not reset the running max nor
   // any registered external boolean or calls to RegisterSigintHandler().
@@ -277,7 +281,7 @@ class TimeLimit {
   double deterministic_limit_;
   double elapsed_deterministic_time_;
 
-  bool* external_boolean_as_limit_;
+  std::atomic<bool>* external_boolean_as_limit_;
 
 #ifdef HAS_PERF_SUBSYSTEM
   // PMU counter to help count the instructions.
@@ -412,7 +416,8 @@ inline double TimeLimit::ReadInstructionCounter() {
 }
 
 inline bool TimeLimit::LimitReached() {
-  if (external_boolean_as_limit_ != nullptr && *external_boolean_as_limit_) {
+  if (external_boolean_as_limit_ != nullptr &&
+      external_boolean_as_limit_->load()) {
     return true;
   }