diff --git a/alsamixer/alsamixer.c b/alsamixer/alsamixer.c
index 3f34fdd..e281923 100644
--- a/alsamixer/alsamixer.c
+++ b/alsamixer/alsamixer.c
@@ -538,13 +538,13 @@ mixer_convert_volume(snd_mixer_elem_t *elem,
 /* update enum list */
 static void update_enum_list(snd_mixer_elem_t *elem, int chn, int delta)
 {
-  int eidx;
+  unsigned int eidx;
   if (snd_mixer_selem_get_enum_item(elem, chn, &eidx) < 0)
     return;
   if (delta < 0) {
-    eidx--;
-    if (eidx < 0)
+    if (eidx == 0)
       return;
+    eidx--;
   } else {
     int items = snd_mixer_selem_get_enum_items(elem);
     if (items < 0)
@@ -800,7 +800,7 @@ static void display_enum_list(snd_mixer_elem_t *elem, int y, int x)
   
   cury = y - 4;
   for (ch = 0; ch < 2; ch++) {
-    int eidx, ofs;
+    unsigned int eidx, ofs;
     char tmp[9];
     err = snd_mixer_selem_get_enum_item(elem, ch, &eidx);
     if (err < 0)
diff --git a/aplay/aplay.c b/aplay/aplay.c
index 1818d43..b6dcc09 100644
--- a/aplay/aplay.c
+++ b/aplay/aplay.c
@@ -86,7 +86,7 @@ static snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK;
 static int mmap_flag = 0;
 static int interleaved = 1;
 static int nonblock = 0;
-static char *audiobuf = NULL;
+static u_char *audiobuf = NULL;
 static snd_pcm_uframes_t chunk_size = 0;
 static unsigned period_time = 0;
 static unsigned buffer_time = 0;
@@ -564,7 +564,7 @@ int main(int argc, char *argv[])
 	chunk_size = 1024;
 	hwparams = rhwparams;
 
-	audiobuf = (char *)malloc(1024);
+	audiobuf = (u_char *)malloc(1024);
 	if (audiobuf == NULL) {
 		error(_("not enough memory"));
 		return 1;
@@ -657,7 +657,7 @@ static int test_vocfile(void *buffer)
  * helper for test_wavefile
  */
 
-size_t test_wavefile_read(int fd, char *buffer, size_t *size, size_t reqsize, int line)
+size_t test_wavefile_read(int fd, u_char *buffer, size_t *size, size_t reqsize, int line)
 {
 	if (*size >= reqsize)
 		return *size;
@@ -682,10 +682,10 @@ size_t test_wavefile_read(int fd, char *buffer, size_t *size, size_t reqsize, in
  *                            == 0 if not
  * Value returned is bytes to be discarded.
  */
-static ssize_t test_wavefile(int fd, char *_buffer, size_t size)
+static ssize_t test_wavefile(int fd, u_char *_buffer, size_t size)
 {
 	WaveHeader *h = (WaveHeader *)_buffer;
-	char *buffer = NULL;
+	u_char *buffer = NULL;
 	size_t blimit = 0;
 	WaveFmtBody *f;
 	WaveChunkHeader *c;
@@ -1418,9 +1418,9 @@ static ssize_t voc_pcm_write(u_char *data, size_t count)
 static void voc_write_silence(unsigned x)
 {
 	unsigned l;
-	char *buf;
+	u_char *buf;
 
-	buf = (char *) malloc(chunk_bytes);
+	buf = (u_char *) malloc(chunk_bytes);
 	if (buf == NULL) {
 		error(_("can't allocate buffer for silence"));
 		return;		/* not fatal error */
diff --git a/seq/aseqnet/aseqnet.c b/seq/aseqnet/aseqnet.c
index 9cb61c2..38de3d9 100644
--- a/seq/aseqnet/aseqnet.c
+++ b/seq/aseqnet/aseqnet.c
@@ -366,7 +366,7 @@ static void start_connection(void)
 {
 	struct sockaddr_in addr;
 	int i;
-	int addr_len;
+	socklen_t addr_len;
 
 	for (i = 0; i < max_connection; i++) {
 		if (netfd[i] < 0)