diff --git a/lasp/c/lasp_siggen.h b/lasp/c/lasp_siggen.h
index 52e7862..5be6cee 100644
--- a/lasp/c/lasp_siggen.h
+++ b/lasp/c/lasp_siggen.h
@@ -85,7 +85,8 @@ Siggen* Siggen_Sweep_create(const d fs,const d fl,const d fu,
  * Obtain a new piece of signal
  * 
  * @param[in] Siggen* Signal generator handle
- * @param[out] samples Samples to fill. Vector should be pre-allocated
+ * @param[out] samples Samples to fill. Vector should be pre-allocated, but
+ * values will be overwritten.
  */
 void Siggen_genSignal(Siggen*,vd* samples);
 /**