diff --git a/src/control/control_hw.c b/src/control/control_hw.c
index aeb2c23e..e9a6be27 100644
--- a/src/control/control_hw.c
+++ b/src/control/control_hw.c
@@ -332,7 +332,7 @@ static int snd_ctl_hw_read(snd_ctl_t *handle, snd_ctl_event_t *event)
 	return 1;
 }
 
-snd_ctl_ops_t snd_ctl_hw_ops = {
+static const snd_ctl_ops_t snd_ctl_hw_ops = {
 	.close = snd_ctl_hw_close,
 	.nonblock = snd_ctl_hw_nonblock,
 	.async = snd_ctl_hw_async,
diff --git a/src/control/control_local.h b/src/control/control_local.h
index f72f2002..fd9f9418 100644
--- a/src/control/control_local.h
+++ b/src/control/control_local.h
@@ -59,7 +59,7 @@ struct _snd_ctl {
 	void *dl_handle;
 	char *name;
 	snd_ctl_type_t type;
-	snd_ctl_ops_t *ops;
+	const snd_ctl_ops_t *ops;
 	void *private_data;
 	int nonblock;
 	int poll_fd;
diff --git a/src/control/control_shm.c b/src/control/control_shm.c
index fbb12366..abab3983 100644
--- a/src/control/control_shm.c
+++ b/src/control/control_shm.c
@@ -397,7 +397,7 @@ static int snd_ctl_shm_read(snd_ctl_t *ctl, snd_ctl_event_t *event)
 	return err;
 }
 
-snd_ctl_ops_t snd_ctl_shm_ops = {
+static const snd_ctl_ops_t snd_ctl_shm_ops = {
 	.close = snd_ctl_shm_close,
 	.nonblock = snd_ctl_shm_nonblock,
 	.async = snd_ctl_shm_async,
diff --git a/src/rawmidi/rawmidi_hw.c b/src/rawmidi/rawmidi_hw.c
index 1f08240d..87829fd7 100644
--- a/src/rawmidi/rawmidi_hw.c
+++ b/src/rawmidi/rawmidi_hw.c
@@ -156,7 +156,7 @@ static ssize_t snd_rawmidi_hw_read(snd_rawmidi_t *rmidi, void *buffer, size_t si
 	return result;
 }
 
-snd_rawmidi_ops_t snd_rawmidi_hw_ops = {
+static const snd_rawmidi_ops_t snd_rawmidi_hw_ops = {
 	.close = snd_rawmidi_hw_close,
 	.nonblock = snd_rawmidi_hw_nonblock,
 	.info = snd_rawmidi_hw_info,
diff --git a/src/rawmidi/rawmidi_local.h b/src/rawmidi/rawmidi_local.h
index 4918c25d..3388502c 100644
--- a/src/rawmidi/rawmidi_local.h
+++ b/src/rawmidi/rawmidi_local.h
@@ -43,7 +43,7 @@ struct _snd_rawmidi {
 	snd_rawmidi_stream_t stream;
 	int mode;
 	int poll_fd;
-	snd_rawmidi_ops_t *ops;
+	const snd_rawmidi_ops_t *ops;
 	void *private_data;
 	size_t buffer_size;
 	size_t avail_min;
diff --git a/src/rawmidi/rawmidi_virt.c b/src/rawmidi/rawmidi_virt.c
index a221f986..52b89849 100644
--- a/src/rawmidi/rawmidi_virt.c
+++ b/src/rawmidi/rawmidi_virt.c
@@ -278,7 +278,7 @@ static ssize_t snd_rawmidi_virtual_read(snd_rawmidi_t *rmidi, void *buffer, size
 	return result;
 }
 
-snd_rawmidi_ops_t snd_rawmidi_virtual_ops = {
+static const snd_rawmidi_ops_t snd_rawmidi_virtual_ops = {
 	.close = snd_rawmidi_virtual_close,
 	.nonblock = snd_rawmidi_virtual_nonblock,
 	.info = snd_rawmidi_virtual_info,
diff --git a/src/seq/seq_hw.c b/src/seq/seq_hw.c
index d0a7b87d..0e945932 100644
--- a/src/seq/seq_hw.c
+++ b/src/seq/seq_hw.c
@@ -381,7 +381,7 @@ static int snd_seq_hw_query_next_port(snd_seq_t *seq, snd_seq_port_info_t *info)
 	return 0;
 }
 
-snd_seq_ops_t snd_seq_hw_ops = {
+static const snd_seq_ops_t snd_seq_hw_ops = {
 	.close = snd_seq_hw_close,
 	.nonblock = snd_seq_hw_nonblock,
 	.system_info = snd_seq_hw_system_info,
diff --git a/src/seq/seq_local.h b/src/seq/seq_local.h
index fa3d95c3..f0a0acd1 100644
--- a/src/seq/seq_local.h
+++ b/src/seq/seq_local.h
@@ -77,7 +77,7 @@ struct _snd_seq {
 	int mode;
 	int poll_fd;
 	void *dl_handle;
-	snd_seq_ops_t *ops;
+	const snd_seq_ops_t *ops;
 	void *private_data;
 	int client;		/* client number */
 	/* buffers */