diff --git a/src/bin/config.cc b/src/bin/config.cc
index 7cf47bd..d9e9320 100644
--- a/src/bin/config.cc
+++ b/src/bin/config.cc
@@ -25,6 +25,7 @@ auto configMap()
     m["--version"] = CNORXZ::Config::version;
     m["--commit"] = CNORXZ::Config::commit;
     m["--flags"] = CNORXZ::Config::flags;
+    m["--definitions"] = CNORXZ::Config::definitions;
     return m;
 }
 
diff --git a/src/include/base/config.h b/src/include/base/config.h
index 63a9871..f86eecd 100644
--- a/src/include/base/config.h
+++ b/src/include/base/config.h
@@ -29,6 +29,9 @@ namespace CNORXZ
 
 	/** return compile flags */
 	String flags();
+
+	/** return compile definitions */
+	String definitions();
     }
 }
 
diff --git a/src/lib/base/config.cc b/src/lib/base/config.cc
index a502939..f701398 100644
--- a/src/lib/base/config.cc
+++ b/src/lib/base/config.cc
@@ -31,5 +31,17 @@ namespace CNORXZ
 	{
 	    return String(CXX_FLAGS);
 	}
+
+	String definitions()
+	{
+	    String o;
+#ifdef HAVE_CEREAL
+	    o += "HAVE_CEREAL ";
+#endif
+#ifdef CXZ_HAVE_AVX
+	    o += "CXZ_HAVE_AVX ";
+#endif
+	    return o;
+	}
     }
 }