Merge pull request #2455 from stchaker/fix_mac_segfault

avoid python C API segfault on intel mac

include/openmc/settings.h

@@ -68,7 +68,12 @@ extern std::string path_input;  //!< directory where main .xml files resides
 extern std::string path_output; //!< directory where output files are written
 extern std::string path_particle_restart; //!< path to a particle restart file
 extern std::string path_sourcepoint;      //!< path to a source file
-extern "C" std::string path_statepoint;   //!< path to a statepoint file
+extern std::string path_statepoint;       //!< path to a statepoint file
+
+// This is required because the c_str() may not be the first thing in
+// std::string. Sometimes it is, but it seems libc++ may not be like that
+// on some computers, like the intel Mac.
+extern "C" const char* path_statepoint_c; //!< C pointer to statepoint file name
 
 extern "C" int32_t n_inactive;         //!< number of inactive batches
 extern "C" int32_t max_lost_particles; //!< maximum number of lost particles

openmc/lib/settings.py

@@ -56,7 +56,7 @@ class _Settings:
 
     @property
     def path_statepoint(self):
-        path = c_char_p.in_dll(_dll, 'path_statepoint').value
+        path = c_char_p.in_dll(_dll, 'path_statepoint_c').value
         return path.decode()
 
     @property

src/initialize.cpp

@@ -193,6 +193,7 @@ int parse_command_line(int argc, char* argv[])
         // Set path and flag for type of run
         if (filetype == "statepoint") {
           settings::path_statepoint = argv[i];
+          settings::path_statepoint_c = settings::path_statepoint.c_str();
           settings::restart_run = true;
         } else if (filetype == "particle restart") {
           settings::path_particle_restart = argv[i];

src/settings.cpp

@@ -82,6 +82,7 @@ std::string path_output;
 std::string path_particle_restart;
 std::string path_sourcepoint;
 std::string path_statepoint;
+const char* path_statepoint_c {path_statepoint.c_str()};
 
 int32_t n_inactive {0};
 int32_t max_lost_particles {10};