1 files changed, 8 insertions, 0 deletions
diff --git a/vm_core.h b/vm_core.h
index 53bf67c2e5..5ddd7b4b4f 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -912,6 +912,10 @@ void rb_ec_initialize_vm_stack(rb_execution_context_t *ec, VALUE *stack, size_t
 // @param ec the execution context to update.
 void rb_ec_clear_vm_stack(rb_execution_context_t *ec);
 
+struct rb_ext_config {
+    bool ractor_safe;
+};
+
 typedef struct rb_ractor_struct rb_ractor_t;
 
 typedef struct rb_thread_struct {
@@ -1000,6 +1004,8 @@ typedef struct rb_thread_struct {
     /* misc */
     VALUE name;
 
+    struct rb_ext_config ext_config;
+
 #ifdef USE_SIGALTSTACK
     void *altstack;
 #endif
@@ -1994,6 +2000,8 @@ extern void rb_reset_coverages(void);
 
 void rb_postponed_job_flush(rb_vm_t *vm);
 
+extern VALUE rb_eRactorUnsafeError; // ractor.c
+
 RUBY_SYMBOL_EXPORT_END
 
 #endif /* RUBY_VM_CORE_H */