3 files changed, 6 insertions, 5 deletions
diff --git a/include/klee/Solver/IncompleteSolver.h b/include/klee/Solver/IncompleteSolver.h
index 8bcf7f88..f026743b 100644
--- a/include/klee/Solver/IncompleteSolver.h
+++ b/include/klee/Solver/IncompleteSolver.h
@@ -104,7 +104,7 @@ public:
                             std::vector< std::vector<unsigned char> > &values,
                             bool &hasSolution);
   SolverRunStatus getOperationStatusCode();
-  char *getConstraintLog(const Query&);
+  std::string getConstraintLog(const Query&) override;
   void setCoreSolverTimeout(time::Span timeout);
 };
 
diff --git a/include/klee/Solver/Solver.h b/include/klee/Solver/Solver.h
index c50b17d8..8679cb87 100644
--- a/include/klee/Solver/Solver.h
+++ b/include/klee/Solver/Solver.h
@@ -15,6 +15,7 @@
 #include "klee/Solver/SolverCmdLine.h"
 
 #include <memory>
+#include <string>
 #include <vector>
 
 namespace klee {
@@ -202,7 +203,7 @@ namespace klee {
     // FIXME: This should go into a helper class, and should handle failure.
     virtual std::pair< ref<Expr>, ref<Expr> > getRange(const Query&);
     
-    virtual char *getConstraintLog(const Query& query);
+    virtual std::string getConstraintLog(const Query& query);
     virtual void setCoreSolverTimeout(time::Span timeout);
   };
 
diff --git a/include/klee/Solver/SolverImpl.h b/include/klee/Solver/SolverImpl.h
index b73370b9..a8b4f8e4 100644
--- a/include/klee/Solver/SolverImpl.h
+++ b/include/klee/Solver/SolverImpl.h
@@ -101,9 +101,9 @@ namespace klee {
     /// status code
     static const char* getOperationStatusString(SolverRunStatus statusCode);
 
-    virtual char *getConstraintLog(const Query& query)  {
-        // dummy
-        return nullptr;
+    virtual std::string getConstraintLog(const Query &query) {
+      // dummy
+      return {};
     }
 
     virtual void setCoreSolverTimeout(time::Span timeout) {};