Use nan of std lib instead of sqrt(-1)

diff --git a/vv/vvSlicer.cxx b/vv/vvSlicer.cxx
index 88c5676c3460174e07665225a7bf8248a4566808..42f83034b7fb78ed38f96ceba186be1d89998bc4 100644 (file)
--- a/vv/vvSlicer.cxx
+++ b/vv/vvSlicer.cxx
@@ -1161,7 +1161,7 @@ double vvSlicer::GetScalarComponentAsDouble(vtkImageData *image, int X, double Y
       iy > image->GetWholeExtent()[3] ||
       iz < image->GetWholeExtent()[4] ||
       iz > image->GetWholeExtent()[5] )
-    return sqrt(-1.);
+    return std::numeric_limits<double>::quiet_NaN();
 
   image->SetUpdateExtent(ix, ix, iy, iy, iz, iz);
   image->Update();