formalization of an API

CMakeLists.txt

@@ -590,7 +590,11 @@ endfunction()
 set(NRN_RUN_FROM_BUILD_DIR_ENV "NEURONHOME=${PROJECT_BINARY_DIR}/share/nrn"
                                "NRNHOME=${PROJECT_BINARY_DIR}")
 prepend_to_var(PATH "${PROJECT_BINARY_DIR}/bin")
-prepend_to_var(LD_LIBRARY_PATH "${PROJECT_BINARY_DIR}/lib")
+if(APPLE)
+  prepend_to_var(DYLD_LIBRARY_PATH "${PROJECT_BINARY_DIR}/lib")
+else()
+  prepend_to_var(LD_LIBRARY_PATH "${PROJECT_BINARY_DIR}/lib")
+endif()
 if(NRN_ENABLE_CORENEURON)
   list(APPEND NRN_RUN_FROM_BUILD_DIR_ENV "CORENRNHOME=${PROJECT_BINARY_DIR}")
 endif()

cmake/NeuronFileLists.cmake

@@ -14,6 +14,7 @@ set(HEADER_FILES_TO_INSTALL
     gnu/nrnran123.h
     nrniv/backtrace_utils.h
     nrniv/bbsavestate.h
+    nrniv/neuronapi.h
     nrnmpi/nrnmpidec.h
     nrnoc/cabvars.h
     nrnoc/md1redef.h
@@ -221,6 +222,7 @@ set(NRNIV_FILE_LIST
     netpar.cpp
     nmodlrandom.cpp
     nonlinz.cpp
+    neuronapi.cpp
     nrncore_write.cpp
     nrncore_write/callbacks/nrncore_callbacks.cpp
     nrncore_write/data/cell_group.cpp

src/ivoc/ivocmain.cpp

@@ -231,6 +231,7 @@ extern void hoc_nrnmpi_init();
 #if NRNMPI_DYNAMICLOAD
 extern void nrnmpi_stubs();
 extern std::string nrnmpi_load();
+void nrnmpi_load_or_exit();
 #endif
 
 // some things are defined in libraries earlier than they are used so...
@@ -805,3 +806,28 @@ int run_til_stdin() {
 }
 void hoc_notify_value() {}
 #endif
+
+
+/// A top-level initialization of MPI given argc and argv.
+/// Sets stubs, load dyn lib, and initializes
+std::tuple<int, const char**> nrn_mpi_setup(int argc, const char** argv) {
+#if defined(AUTO_DLOPEN_NRNMECH) && AUTO_DLOPEN_NRNMECH == 0
+    extern int nrn_noauto_dlopen_nrnmech;
+    nrn_noauto_dlopen_nrnmech = 1;
+#endif
+
+#if NRNMPI
+#if NRNMPI_DYNAMICLOAD
+    nrnmpi_stubs();
+    for (int i = 1; i < argc; ++i) {
+        if (strcmp("-mpi", argv[i]) == 0) {
+            nrnmpi_load_or_exit();
+            break;
+        }
+    }
+#endif                                           // NRNMPI_DYNAMICLOAD
+    auto argv_ptr = const_cast<char***>(&argv);  // safe if individual strings not modified
+    nrnmpi_init(1, &argc, argv_ptr);             // may change argc and argv
+#endif                                           // NRNMPI
+    return {argc, argv};
+}

src/neuron/cache/mechanism_range.hpp

@@ -15,7 +15,7 @@ namespace neuron::cache {
 template <typename Callable>
 void indices_to_cache(short type, Callable callable) {
     auto const pdata_size = nrn_prop_dparam_size_[type];
-    auto* const dparam_semantics = memb_func[type].dparam_semantics;
+    auto* const dparam_semantics = memb_func[type].dparam_semantics.get();
     for (int field = pdata_size - 1; field >= 0; --field) {
         // Check if the field-th dparam of this mechanism type is an ion variable. See
         // hoc_register_dparam_semantics.