diff --git a/client/work_fetch.cpp b/client/work_fetch.cpp
index 9abd610965..68bb047e24 100644
--- a/client/work_fetch.cpp
+++ b/client/work_fetch.cpp
@@ -15,6 +15,8 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
 
+#include <cmath>
+
 #include "cpp.h"
 
 #ifdef _WIN32