From f2d35a96a0cf639b7a603533323ef702c84c00ac Mon Sep 17 00:00:00 2001
From: Lars Kanis <lars@greiz-reinsdorf.de>
Date: Tue, 9 Jun 2020 15:53:00 +0200
Subject: [PATCH] Add a spec regarding issue #788

---
 spec/ffi/library_spec.rb | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/spec/ffi/library_spec.rb b/spec/ffi/library_spec.rb
index ff18f9b71..b622a29ac 100644
--- a/spec/ffi/library_spec.rb
+++ b/spec/ffi/library_spec.rb
@@ -64,6 +64,20 @@ class StructUCDP < FFI::Struct
     end
   end
 
+  if RbConfig::CONFIG['host_os'] =~ /mingw/
+    # See https://github.com/ffi/ffi/issues/788
+    it "libc functions shouldn't call an invalid parameter handler" do
+      mod = Module.new do
+        extend FFI::Library
+        ffi_lib 'c'
+        attach_function(:get_osfhandle, :_get_osfhandle, [:int], :intptr_t)
+      end
+
+      expect( mod.get_osfhandle(42) ).to eq(-1)
+    end
+  end
+
+
   describe "ffi_lib" do
     it "empty name list should raise error" do
       expect {