From 072956924b0c086e00395dcf1ce6fdda3af0f4a5 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.alekhin@intel.com>
Date: Wed, 25 Jan 2017 15:16:10 +0300
Subject: [PATCH] build: fix build error

---
 modules/xfeatures2d/src/affine_feature2d.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/xfeatures2d/src/affine_feature2d.cpp b/modules/xfeatures2d/src/affine_feature2d.cpp
index 60f43bf57..ac60a569a 100644
--- a/modules/xfeatures2d/src/affine_feature2d.cpp
+++ b/modules/xfeatures2d/src/affine_feature2d.cpp
@@ -211,7 +211,7 @@ bool calcAffineAdaptation(const Mat & fimage, Elliptic_KeyPoint & keypoint)
             float ratio = 1 - q;
 
             //if ratio == 1 means q == 0 and one axes equals to 0
-            if (!isnan(ratio) && ratio != 1)
+            if (!cvIsNaN(ratio) && ratio != 1)
             {
                 //Update U matrix
                 U = U * Mk;