[ruby/fiddle] Add support for variadic arguments

GitHub: fix GH-39

Reported by kojix2. Thanks!!!

https://github.com/ruby/fiddle/commit/6c4cb904dc

2 files changed, 32 insertions, 1 deletions

diff --git a/test/fiddle/test_func.rb b/test/fiddle/test_func.rb
index ca89173766..18052fffdd 100644
--- a/test/fiddle/test_func.rb
+++ b/test/fiddle/test_func.rb
@@ -79,5 +79,36 @@ module Fiddle
       EnvUtil.under_gc_stress {qsort.call(buff, buff.size, 1, cb)}
       assert_equal("1349", buff, bug4929)
     end
+
+    def test_snprintf
+      snprintf = Function.new(@libc["snprintf"],
+                              [
+                                TYPE_VOIDP,
+                                TYPE_SIZE_T,
+                                TYPE_VOIDP,
+                                TYPE_VARIADIC,
+                              ],
+                              TYPE_INT)
+      output_buffer = " " * 1024
+      output = Pointer[output_buffer]
+
+      written = snprintf.call(output,
+                              output.size,
+                              "int: %d, string: %.*s\n",
+                              TYPE_INT, -29,
+                              TYPE_INT, 4,
+                              TYPE_VOIDP, "Hello")
+      assert_equal("int: -29, string: Hell\n",
+                   output_buffer[0, written])
+
+      written = snprintf.call(output,
+                              output.size,
+                              "string: %.*s, uint: %u\n",
+                              TYPE_INT, 2,
+                              TYPE_VOIDP, "Hello",
+                              TYPE_INT, 29)
+      assert_equal("string: He, uint: 29\n",
+                   output_buffer[0, written])
+    end
   end
 end if defined?(Fiddle)
diff --git a/test/fiddle/test_import.rb b/test/fiddle/test_import.rb
index fce8b864d9..c56d81c351 100644
--- a/test/fiddle/test_import.rb
+++ b/test/fiddle/test_import.rb
@@ -110,7 +110,7 @@ module Fiddle
       assert_equal(SIZEOF_LONG_LONG, LIBC.sizeof("long long")) if defined?(SIZEOF_LONG_LONG)
     end
 
-    Fiddle.constants.grep(/\ATYPE_(?!VOID\z)(.*)/) do
+    Fiddle.constants.grep(/\ATYPE_(?!VOID|VARIADIC\z)(.*)/) do
       type = $&
       size = Fiddle.const_get("SIZEOF_#{$1}")
       name = $1.sub(/P\z/,"*").gsub(/_(?!T\z)/, " ").downcase