2 files changed, 14 insertions, 0 deletions
diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 1feb9231db..d5753a97a0 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -1602,6 +1602,13 @@ strio_pread(int argc, VALUE *argv, VALUE self)
         rb_raise(rb_eArgError, "negative string size (or size too big): %" PRIsVALUE, rb_len);
     }
 
+    if (len == 0) {
+        if (NIL_P(rb_buf)) {
+            return rb_str_new("", 0);
+        }
+        return rb_buf;
+    }
+
     if (offset < 0) {
         rb_syserr_fail_str(EINVAL, rb_sprintf("pread: Invalid offset argument: %" PRIsVALUE, rb_offset));
     }
diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index d2d96c5719..cb82841231 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -750,6 +750,13 @@ class TestStringIO < Test::Unit::TestCase
     assert_raise(EOFError) { f.pread(1, 5) }
     assert_raise(ArgumentError) { f.pread(-1, 0) }
     assert_raise(Errno::EINVAL) { f.pread(3, -1) }
+
+    assert_equal "".b, StringIO.new("").pread(0, 0)
+    assert_equal "".b, StringIO.new("").pread(0, -10)
+
+    buf = "stale".b
+    assert_equal "stale".b, StringIO.new("").pread(0, 0, buf)
+    assert_equal "stale".b, buf
   end
 
   def test_size