From: Denis Davydov <davydden@gmail.com>
Date: Tue, 30 Oct 2018 15:52:48 +0000 (+0100)
Subject: add mutex lock
X-Git-Tag: v9.1.0-rc1~588^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F7375%2Fhead;p=dealii.git

add mutex lock
---

diff --git a/source/base/incremental_function.cc b/source/base/incremental_function.cc
index 49bde1148c..18091c358d 100644
--- a/source/base/incremental_function.cc
+++ b/source/base/incremental_function.cc
@@ -50,6 +50,10 @@ namespace Functions
     const Point<dim> & p,
     const unsigned int comp) const
   {
+    // since we modify a mutable member variable, lock the
+    // the data via a mutex
+    std::lock_guard<std::mutex> lock(mutex);
+
     // Cache the time state of the base class in case it has been changed
     // within the user code. We reset the wrapped function to the original
     // state once we're done with our own evaluations.