diff --git a/src/if_ruby.c b/src/if_ruby.c

index 9c91f31..e53e0ef 100644

--- a/src/if_ruby.c

+++ b/src/if_ruby.c

@@ -476,7 +476,11 @@ static void (*dll_ruby_init_stack)(VALUE*);

 #  endif

 # endif

 # ifdef RUBY19_OR_LATER

+#  if DYNAMIC_RUBY_VER >= 26

+static VALUE (*dll_rb_int2big)(intptr_t);

+#  else

 static VALUE (*dll_rb_int2big)(SIGNED_VALUE);

+#  endif

 # endif

 # ifdef RUBY19_OR_LATER

@@ -506,7 +510,11 @@ SIGNED_VALUE rb_num2long_stub(VALUE x)

 {

     return dll_rb_num2long(x);

 }

+# if DYNAMIC_RUBY_VER >= 26

+VALUE rb_int2big_stub(intptr_t x)

+# else

 VALUE rb_int2big_stub(SIGNED_VALUE x)

+# endif

 {

     return dll_rb_int2big(x);

 }