From f70cc112f0c0ea2a3fbac47bc092ce165fb98135 Mon Sep 17 00:00:00 2001
From: Ivan Smirnov <i.s.smirnov@gmail.com>
Date: Sat, 22 Oct 2016 10:50:39 +0100
Subject: [PATCH] Make dtype from string ctor accept const ref

---
 include/pybind11/numpy.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index 04001d6c5..588cc1519 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -170,7 +170,7 @@ public:
         m_ptr = descr.strip_padding().release().ptr();
     }
 
-    explicit dtype(std::string format) {
+    explicit dtype(const std::string &format) {
         m_ptr = from_args(pybind11::str(format)).release().ptr();
     }