diff --git a/lib/cpp/Makefile.am b/lib/cpp/Makefile.am
index 77d4d6c..4441fba 100755
--- a/lib/cpp/Makefile.am
+++ b/lib/cpp/Makefile.am
@@ -62,7 +62,7 @@
 endif
 
 AM_CXXFLAGS = -Wall -Wextra -pedantic
-AM_CPPFLAGS = $(BOOST_CPPFLAGS) $(OPENSSL_INCLUDES) -I$(srcdir)/src -D__STDC_LIMIT_MACROS
+AM_CPPFLAGS = $(BOOST_CPPFLAGS) $(OPENSSL_INCLUDES) -I$(srcdir)/src -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
 
 # Define the source files for the module