diff --git a/include/villas/sample.h b/include/villas/sample.h
index b6684bdbc..25660aace 100644
--- a/include/villas/sample.h
+++ b/include/villas/sample.h
@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <complex.h>
 #include <time.h>
 
 #ifdef __cplusplus
@@ -87,6 +88,8 @@ struct sample {
 	union {
 		double  f;	/**< Floating point values. */
 		int64_t i;	/**< Integer values. */
+		bool	b;	/**< Boolean values. */
+		float complex z; /**< Complex values. */
 	} data[];		/**< Data is in host endianess! */
 };
 
diff --git a/include/villas/signal.h b/include/villas/signal.h
index 590f5932a..e75cefff5 100644
--- a/include/villas/signal.h
+++ b/include/villas/signal.h
@@ -37,6 +37,7 @@ enum signal_format {
 	SIGNAL_FORMAT_FLOAT	= 0,
 	SIGNAL_FORMAT_INT	= 1,
 	SIGNAL_FORMAT_BOOL 	= 2,
+	SIGNAL_FORMAT_COMPLEX 	= 3,
 	SIGNAL_FORMAT_UNKNOWN	= -1
 };