diff --git a/src/dsd2pcm/dsd2pcm.c b/src/dsd2pcm/dsd2pcm.c
index 31f9a106d..315820f60 100644
--- a/src/dsd2pcm/dsd2pcm.c
+++ b/src/dsd2pcm/dsd2pcm.c
@@ -87,7 +87,7 @@ static float ctables[CTABLES][256];
 static unsigned char bitreverse[256];
 static int precalculated = 0;
 
-static void precalc()
+static void precalc(void)
 {
 	int t, e, m, k;
 	double acc;
@@ -117,7 +117,7 @@ struct dsd2pcm_ctx_s
 	unsigned fifopos;
 };
 
-extern dsd2pcm_ctx* dsd2pcm_init()
+extern dsd2pcm_ctx* dsd2pcm_init(void)
 {
 	dsd2pcm_ctx* ptr;
 	if (!precalculated) precalc();
diff --git a/src/dsd2pcm/dsd2pcm.h b/src/dsd2pcm/dsd2pcm.h
index 26f6b6f10..80e8ce0cc 100644
--- a/src/dsd2pcm/dsd2pcm.h
+++ b/src/dsd2pcm/dsd2pcm.h
@@ -20,7 +20,7 @@ typedef struct dsd2pcm_ctx_s dsd2pcm_ctx;
  * POSIX thread-safety definition because it modifies global state
  * (lookup tables are computed during the first call)
  */
-extern dsd2pcm_ctx* dsd2pcm_init();
+extern dsd2pcm_ctx* dsd2pcm_init(void);
 
 /**
  * deinitializes a "dsd2pcm engine"