diff --git a/core/src/linuxcnc_rs274_backend.cpp b/core/src/linuxcnc_rs274_backend.cpp
index 4a7769c..351a574 100644
--- a/core/src/linuxcnc_rs274_backend.cpp
+++ b/core/src/linuxcnc_rs274_backend.cpp
@@ -82,6 +82,37 @@ bool file_mode_enabled() {
     return std::getenv("CNC_SIM_RS274_FILE_MODE") != nullptr;
 }
 
+class ScopedEnvironmentVariable {
+public:
+    ScopedEnvironmentVariable(const char *name, const std::string &value) : name_(name), active_(!value.empty()) {
+        if (!active_) {
+            return;
+        }
+        if (const char *old = std::getenv(name_)) {
+            had_old_ = true;
+            old_ = old;
+        }
+        setenv(name_, value.c_str(), 1);
+    }
+
+    ~ScopedEnvironmentVariable() {
+        if (!active_) {
+            return;
+        }
+        if (had_old_) {
+            setenv(name_, old_.c_str(), 1);
+        } else {
+            unsetenv(name_);
+        }
+    }
+
+private:
+    const char *name_;
+    bool active_;
+    bool had_old_ = false;
+    std::string old_;
+};
+
 #ifndef CNC_SIM_ENABLE_LINUXCNC_WASM_SAFE_PROBE
 bool write_temp_program(const char *program,
                         size_t program_len,
@@ -197,6 +228,9 @@ int parse_linuxcnc_rs274_backend(CanonEventSink &sink,
     sink.clear_callback_status();
     cnc_sim_linuxcnc_set_canon_sink(&sink);
 
+    // LinuxCNC source basis: rs274ngc_pre.cc and interp_namedparams.cc read
+    // INI_FILE_NAME for startup and #<_ini[section]key> named parameters.
+    ScopedEnvironmentVariable ini_file_env("INI_FILE_NAME", options.ini_file_name);
     InterpBase *interp = makeInterp();
     if (!options.ini_file_name.empty()) {
         // LinuxCNC source basis: emctask.cc calls Interp::ini_load() before
diff --git a/core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp b/core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp
index c33733f..6275864 100644
--- a/core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp
+++ b/core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp
@@ -240,6 +240,8 @@ int main() {
             std::ofstream ini_file(rs274_ini_path);
             ini_file << "[RS274NGC]\n";
             ini_file << "PARAMETER_FILE = " << ini_parameter_var_path << "\n";
+            ini_file << "[SETUP]\n";
+            ini_file << "XPOS = 12\n";
         }
         std::vector<CncSimEvent> ini_events;
         CncSimHandle *ini_sim = cnc_sim_create();
@@ -255,23 +257,33 @@ int main() {
         const char ini_parameter_check_program[] =
             "G21 G90 G17\n"
             "F100\n"
-            "G1 X#5001\n";
+            "G1 X#5001\n"
+            "G1 X#<_ini[setup]xpos>\n";
         ini_ok &= expect(cnc_sim_parse_program(ini_sim,
                                                ini_parameter_check_program,
                                                sizeof(ini_parameter_check_program) - 1) == 0,
                          cnc_sim_last_error(ini_sim));
         bool saw_ini_parameter_restore = false;
+        bool saw_ini_named_parameter = false;
         for (const auto &event : ini_events) {
             saw_ini_parameter_restore = saw_ini_parameter_restore ||
                                         (event.type == CNC_SIM_EVENT_LINEAR_FEED &&
                                          event.line == 3 &&
                                          near(event.end.x, 44.0));
+            saw_ini_named_parameter = saw_ini_named_parameter ||
+                                      (event.type == CNC_SIM_EVENT_LINEAR_FEED &&
+                                       event.line == 4 &&
+                                       near(event.end.x, 12.0));
         }
         // LinuxCNC source basis: emctask.cc calls interp.ini_load(), and
         // rs274ngc_pre.cc ini_load() maps [RS274NGC] PARAMETER_FILE through
         // SET_PARAMETER_FILE_NAME before rs274_ngc_init() restores parameters.
         ini_ok &= expect(saw_ini_parameter_restore,
                          "expected LinuxCNC INI PARAMETER_FILE to restore numbered parameters");
+        // LinuxCNC source basis: rs274ngc_pre.cc and interp_namedparams.cc
+        // read INI_FILE_NAME for #<_ini[section]key> lookups.
+        ini_ok &= expect(saw_ini_named_parameter,
+                         "expected LinuxCNC config INI_FILE_NAME to back #<_ini[]> named parameters");
         cnc_sim_destroy(ini_sim);
         if (!ini_ok) {
             return 1;
diff --git a/test-native.sh b/test-native.sh
index babbf77..6ac7229 100755
--- a/test-native.sh
+++ b/test-native.sh
@@ -82,7 +82,9 @@ grep -F 'blocked:src/emc/rs274ngc/gcodemodule.cc:Python gcode module binding, tr
 grep -F 'expected LinuxCNC parameter env override not to leak into default parses' core/tests/cnc_sim_api_smoke.cpp >/dev/null
 grep -F 'SET_PARAMETER_FILE_NAME("rs274ngc.var")' core/src/linuxcnc_rs274_backend.cpp >/dev/null
 grep -F 'expected LinuxCNC INI PARAMETER_FILE to restore numbered parameters' core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp >/dev/null
+grep -F 'expected LinuxCNC config INI_FILE_NAME to back #<_ini[]> named parameters' core/tests/cnc_sim_api_linuxcnc_rs274_smoke.cpp >/dev/null
 grep -F 'interp->ini_load(options.ini_file_name.c_str())' core/src/linuxcnc_rs274_backend.cpp >/dev/null
+grep -F 'ScopedEnvironmentVariable ini_file_env("INI_FILE_NAME", options.ini_file_name)' core/src/linuxcnc_rs274_backend.cpp >/dev/null
 grep -F 'metadata:src/emc/nml_intf/emcops.cc:source basis for native source-link EMC status constructor support object' linuxcnc-rs274-source-files.txt >/dev/null
 grep -F 'metadata:src/emc/sai/dummyemcstat.cc:source basis for native source-link emcStatus singleton support object' linuxcnc-rs274-source-files.txt >/dev/null
 grep -F 'metadata:src/emc/sai/Submakefile:LinuxCNC SAI build metadata defining dummyemcstat support object' linuxcnc-rs274-source-files.txt >/dev/null