diff --git a/axfer/container-au.c b/axfer/container-au.c
index 6459b16..cccbebd 100644
--- a/axfer/container-au.c
+++ b/axfer/container-au.c
@@ -76,7 +76,7 @@ static int au_parser_pre_process(struct container_context *cntr,
 	struct parser_state *state = cntr->private_data;
 	struct container_header header;
 	enum code_id code_id;
-	int i;
+	unsigned int i;
 	int err;
 
 	// Parse header. 4 bytes are enough to detect supported containers.
@@ -153,7 +153,7 @@ static int au_builder_pre_process(struct container_context *cntr,
 				  uint64_t *byte_count)
 {
 	struct builder_state *status = cntr->private_data;
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(format_maps); ++i) {
 		if (format_maps[i].format == *format)
diff --git a/axfer/container-raw.c b/axfer/container-raw.c
index 9b0022e..071f94c 100644
--- a/axfer/container-raw.c
+++ b/axfer/container-raw.c
@@ -13,10 +13,10 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-static int raw_builder_pre_process(struct container_context *cntr,
-				   snd_pcm_format_t *sample_format,
-				   unsigned int *samples_per_frame,
-				   unsigned int *frames_per_second,
+static int raw_builder_pre_process(struct container_context *,
+				   snd_pcm_format_t *,
+				   unsigned int *,
+				   unsigned int *,
 				   uint64_t *byte_count)
 {
 	*byte_count = UINT64_MAX;
@@ -25,9 +25,9 @@ static int raw_builder_pre_process(struct container_context *cntr,
 }
 
 static int raw_parser_pre_process(struct container_context *cntr,
-				  snd_pcm_format_t *sample_format,
-				  unsigned int *samples_per_frame,
-				  unsigned int *frames_per_second,
+				  snd_pcm_format_t *,
+				  unsigned int *,
+				  unsigned int *,
 				  uint64_t *byte_count)
 {
 	struct stat buf = {0};
diff --git a/axfer/container-riff-wave.c b/axfer/container-riff-wave.c
index d68401d..f62cdbd 100644
--- a/axfer/container-riff-wave.c
+++ b/axfer/container-riff-wave.c
@@ -349,7 +349,7 @@ static int wave_parser_pre_process(struct container_context *cntr,
 	struct parser_state *state = cntr->private_data;
 	int phys_width;
 	const struct format_map *map;
-	int i;
+	unsigned int i;
 	int err;
 
 	err = parse_riff_wave_format(cntr);
@@ -363,7 +363,7 @@ static int wave_parser_pre_process(struct container_context *cntr,
 		map = &format_maps[i];
 		if (state->format != map->wformat)
 			continue;
-		if (state->avail_bits_in_sample !=
+		if ((int)state->avail_bits_in_sample !=
 					snd_pcm_format_width(map->format))
 			continue;
 		if (phys_width != snd_pcm_format_physical_width(map->format))
@@ -514,7 +514,7 @@ static int wave_builder_pre_process(struct container_context *cntr,
 				    uint64_t *byte_count)
 {
 	struct builder_state *state = cntr->private_data;
-	int i;
+	unsigned int i;
 
 	// Validate parameters.
 	for (i = 0; i < ARRAY_SIZE(format_maps); ++i) {
diff --git a/axfer/container-voc.c b/axfer/container-voc.c
index 5941003..f169a1a 100644
--- a/axfer/container-voc.c
+++ b/axfer/container-voc.c
@@ -221,7 +221,7 @@ static int build_time_constant(unsigned int frames_per_second,
 			       unsigned int samples_per_frame, uint16_t *code,
 			       bool extended)
 {
-	int i;
+	unsigned int i;
 
 	// 16 bits are available for this purpose.
 	if (extended) {
@@ -264,7 +264,7 @@ static unsigned int parse_time_constant(uint16_t code,
 					unsigned int *frames_per_second,
 					bool extended)
 {
-	int i;
+	unsigned int i;
 
 	if (extended) {
 		if (samples_per_frame > 2)
@@ -344,7 +344,7 @@ static int parse_container_header(struct parser_state *state,
 
 static bool check_code_id(uint8_t code_id, unsigned int version)
 {
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(format_maps); ++i) {
 		if (code_id != format_maps[i].code_id)
@@ -560,7 +560,7 @@ static int voc_parser_pre_process(struct container_context *cntr,
 				  uint64_t *byte_count)
 {
 	struct parser_state *state = cntr->private_data;
-	int i;
+	unsigned int i;
 	int err;
 
 	err = detect_container_version(cntr);
@@ -719,7 +719,7 @@ static int voc_builder_pre_process(struct container_context *cntr,
 				   uint64_t *byte_count)
 {
 	struct builder_state *state = cntr->private_data;
-	int i;
+	unsigned int i;
 
 	// Validate parameters.
 	for (i = 0; i < ARRAY_SIZE(format_maps); ++i) {
diff --git a/axfer/container.c b/axfer/container.c
index 379b72f..a325fef 100644
--- a/axfer/container.c
+++ b/axfer/container.c
@@ -34,7 +34,7 @@ static const char *const suffixes[] = {
 	[CONTAINER_FORMAT_RAW]		= "",
 };
 
-const char *const container_suffix_from_format(enum container_format format)
+const char * container_suffix_from_format(enum container_format format)
 {
 	return suffixes[format];
 }
@@ -100,7 +100,7 @@ enum container_format container_format_from_path(const char *path)
 	const char *pos;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(suffixes); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(suffixes); ++i) {
 		suffix = suffixes[i];
 
 		// Check last part of the string.
@@ -186,7 +186,7 @@ int container_parser_init(struct container_context *cntr, int fd,
 	err = container_recursive_read(cntr, cntr->magic, sizeof(cntr->magic));
 	if (err < 0)
 		return err;
-	for (i = 0; i < ARRAY_SIZE(parsers); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(parsers); ++i) {
 		parser = parsers[i];
 		size = strlen(parser->magic);
 		if (size > 4)
diff --git a/axfer/container.h b/axfer/container.h
index 8f7ab2a..ab162c8 100644
--- a/axfer/container.h
+++ b/axfer/container.h
@@ -60,7 +60,7 @@ struct container_context {
 	uint64_t handled_byte_count;
 };
 
-const char *const container_suffix_from_format(enum container_format format);
+const char *container_suffix_from_format(enum container_format format);
 enum container_format container_format_from_path(const char *path);
 int container_parser_init(struct container_context *cntr, int fd,
 			  unsigned int verbose);
diff --git a/axfer/frame-cache.c b/axfer/frame-cache.c
index 417c1e6..8538f1e 100644
--- a/axfer/frame-cache.c
+++ b/axfer/frame-cache.c
@@ -33,7 +33,7 @@ static void align_frames_in_n(struct frame_cache *cache,
 	char **buf_ptrs = cache->buf_ptr;
 	unsigned int offset;
 	unsigned int size;
-	int i;
+	unsigned int i;
 
 	cache->remained_count -= consumed_count;
 
@@ -75,7 +75,7 @@ int frame_cache_init(struct frame_cache *cache, snd_pcm_access_t access,
 	} else {
 		char **bufs = calloc(samples_per_frame, sizeof(*bufs));
 		char **buf_ptrs = calloc(samples_per_frame, sizeof(*buf_ptrs));
-		int i;
+		unsigned int i;
 
 		cache->buf = bufs;
 		cache->buf_ptr = buf_ptrs;
@@ -102,7 +102,7 @@ void frame_cache_destroy(struct frame_cache *cache)
 	if (cache->access == SND_PCM_ACCESS_RW_NONINTERLEAVED) {
 		char **bufs = cache->buf;
 		if (bufs) {
-			int i;
+			unsigned int i;
 			for (i = 0; i < cache->samples_per_frame; ++i)
 				free(bufs[i]);
 		}
diff --git a/axfer/main.c b/axfer/main.c
index 21d3b4a..765d2c3 100644
--- a/axfer/main.c
+++ b/axfer/main.c
@@ -107,7 +107,7 @@ static bool decide_subcmd(int argc, char *const *argv, enum subcmds *subcmd)
 		return false;
 
 	// Original command system. For long options.
-	for (i = 0; i < ARRAY_SIZE(long_opts); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(long_opts); ++i) {
 		for (j = 0; j < argc; ++j) {
 			if (!strcmp(long_opts[i].name, argv[j])) {
 				*subcmd = long_opts[i].subcmd;
@@ -123,7 +123,7 @@ static bool decide_subcmd(int argc, char *const *argv, enum subcmds *subcmd)
 		    argv[i][1] == '-' || argv[i][1] == '\0')
 			continue;
 		for (pos = argv[i]; *pos != '\0'; ++pos) {
-			for (j = 0; j < ARRAY_SIZE(short_opts); ++j) {
+			for (j = 0; j < (int)ARRAY_SIZE(short_opts); ++j) {
 				if (*pos == short_opts[j].c) {
 					*subcmd = short_opts[j].subcmd;
 					return true;
@@ -161,7 +161,7 @@ static bool decide_direction(int argc, char *const *argv,
 	char *pos;
 
 	// Original command system. For long options.
-	for (i = 0; i < ARRAY_SIZE(long_opts); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(long_opts); ++i) {
 		for (j = 0; j < argc; ++j) {
 			if (!strcmp(long_opts[i].name, argv[j])) {
 				*direction = long_opts[i].direction;
@@ -177,7 +177,7 @@ static bool decide_direction(int argc, char *const *argv,
 		    argv[i][1] == '-' || argv[i][1] == '\0')
 			continue;
 		for (pos = argv[i]; *pos != '\0'; ++pos) {
-			for (j = 0; j < ARRAY_SIZE(short_opts); ++j) {
+			for (j = 0; j < (int)ARRAY_SIZE(short_opts); ++j) {
 				if (*pos == short_opts[j].c) {
 					*direction = short_opts[j].direction;
 					return true;
@@ -187,7 +187,7 @@ static bool decide_direction(int argc, char *const *argv,
 	}
 
 	// If not decided yet, judge according to command name.
-	for (i = 0; i < ARRAY_SIZE(aliases); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(aliases); ++i) {
 		for (pos = argv[0] + strlen(argv[0]); pos != argv[0]; --pos) {
 			if (strstr(pos, aliases[i]) != NULL) {
 				*direction = i;
@@ -212,7 +212,7 @@ static bool detect_subcmd(int argc, char *const *argv, enum subcmds *subcmd)
 	if (argc < 2)
 		return false;
 
-	for (i = 0; i < ARRAY_SIZE(subcmds); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(subcmds); ++i) {
 		if (!strcmp(argv[1], subcmds[i])) {
 			*subcmd = i;
 			return true;
diff --git a/axfer/mapper-multiple.c b/axfer/mapper-multiple.c
index 00569af..8e82b22 100644
--- a/axfer/mapper-multiple.c
+++ b/axfer/mapper-multiple.c
@@ -27,7 +27,7 @@ static void align_to_i(void *frame_buf, unsigned int frame_count,
 	unsigned int dst_pos;
 	unsigned int src_pos;
 	struct container_context *cntr;
-	int i, j;
+	unsigned int i, j;
 
 	// src: first channel in each of interleaved buffers in containers =>
 	// dst:interleaved.
@@ -55,7 +55,7 @@ static void align_from_i(void *frame_buf, unsigned int frame_count,
 	unsigned int src_pos;
 	unsigned int dst_pos;
 	struct container_context *cntr;
-	int i, j;
+	unsigned int i, j;
 
 	for (i = 0; i < cntr_count; ++i) {
 		dst = dst_bufs[i];
@@ -77,7 +77,7 @@ static int multiple_pre_process(struct mapper_context *mapper,
 {
 	struct multiple_state *state = mapper->private_data;
 	struct container_context *cntr;
-	int i;
+	unsigned int i;
 
 	// Additionally, format of samples in the containers should be the same
 	// as the format in PCM substream.
@@ -151,7 +151,7 @@ static int process_containers(char **src_bufs, unsigned int *frame_count,
 {
 	struct container_context *cntr;
 	char *src;
-	int i;
+	unsigned int i;
 	int err = 0;
 
 	// TODO: arrangement for *frame_count.
@@ -226,7 +226,7 @@ static int multiple_demuxer_process_frames(struct mapper_context *mapper,
 static void multiple_post_process(struct mapper_context *mapper)
 {
 	struct multiple_state *state = mapper->private_data;
-	int i;
+	unsigned int i;
 
 	if (state->bufs) {
 		for (i = 0; i < state->cntr_count; ++i) {
diff --git a/axfer/mapper-single.c b/axfer/mapper-single.c
index aa8aa19..13e7fc5 100644
--- a/axfer/mapper-single.c
+++ b/axfer/mapper-single.c
@@ -24,7 +24,7 @@ static void align_to_vector(void *frame_buf, unsigned int frame_count,
 	char *dst;
 	unsigned int src_pos;
 	unsigned int dst_pos;
-	int i, j;
+	unsigned int i, j;
 
 	// src: interleaved => dst: a set of interleaved buffers.
 	for (i = 0; i < samples_per_frame; ++i) {
@@ -46,7 +46,7 @@ static void align_from_vector(void *frame_buf, unsigned int frame_count,
 	char *src;
 	unsigned int dst_pos;
 	unsigned int src_pos;
-	int i, j;
+	unsigned int i, j;
 
 	// src: a set of interleaved buffers => dst:interleaved.
 	for (i = 0; i < samples_per_frame; ++i) {
@@ -62,7 +62,7 @@ static void align_from_vector(void *frame_buf, unsigned int frame_count,
 
 static int single_pre_process(struct mapper_context *mapper,
 			      struct container_context *cntrs,
-			      unsigned int cntr_count)
+			      unsigned int)
 {
 	struct single_state *state = mapper->private_data;
 	unsigned int bytes_per_buffer;
@@ -110,7 +110,7 @@ static int single_muxer_process_frames(struct mapper_context *mapper,
 				       void *frame_buf,
 				       unsigned int *frame_count,
 				       struct container_context *cntrs,
-				       unsigned int cntr_count)
+				       unsigned int)
 {
 	struct single_state *state = mapper->private_data;
 	void *src;
@@ -141,7 +141,7 @@ static int single_demuxer_process_frames(struct mapper_context *mapper,
 					 void *frame_buf,
 					 unsigned int *frame_count,
 					 struct container_context *cntrs,
-					 unsigned int cntr_count)
+					 unsigned int)
 {
 	struct single_state *state = mapper->private_data;
 	void *dst;
diff --git a/axfer/subcmd-list.c b/axfer/subcmd-list.c
index 359f73f..f9c8e0f 100644
--- a/axfer/subcmd-list.c
+++ b/axfer/subcmd-list.c
@@ -19,10 +19,9 @@ enum list_op {
 };
 
 static int dump_device(snd_ctl_t *handle, const char *id, const char *name,
-		       snd_pcm_stream_t direction, snd_pcm_info_t *info)
+		       snd_pcm_stream_t, snd_pcm_info_t *info)
 {
-	unsigned int count;
-	int i;
+	unsigned int i, count;
 	int err;
 
 	printf("card %i: %s [%s], device %i: %s [%s]\n",
@@ -44,7 +43,7 @@ static int dump_device(snd_ctl_t *handle, const char *id, const char *name,
 			continue;
 		}
 
-		printf("  Subdevice #%i: %s\n",
+		printf("  Subdevice #%u: %s\n",
 		       i, snd_pcm_info_get_subdevice_name(info));
 	}
 
@@ -242,7 +241,7 @@ static int detect_operation(int argc, char *const *argv, enum list_op *op)
 	if (argc < 2)
 		return false;
 
-	for (i = 0; i < ARRAY_SIZE(ops); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(ops); ++i) {
 		if (!strcmp(argv[1], ops[i])) {
 			*op = i;
 			return true;
diff --git a/axfer/subcmd-transfer.c b/axfer/subcmd-transfer.c
index 839215a..b39fde8 100644
--- a/axfer/subcmd-transfer.c
+++ b/axfer/subcmd-transfer.c
@@ -31,7 +31,7 @@ static struct context *ctx_ptr;
 
 static void handle_unix_signal_for_finish(int sig)
 {
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < ctx_ptr->cntr_count; ++i)
 		ctx_ptr->cntrs[i].interrupted = true;
@@ -40,7 +40,7 @@ static void handle_unix_signal_for_finish(int sig)
 	ctx_ptr->interrupted = true;
 }
 
-static void handle_unix_signal_for_suspend(int sig)
+static void handle_unix_signal_for_suspend(int)
 {
 	sigset_t curr, prev;
 	struct sigaction sa = {0};
@@ -170,7 +170,7 @@ static int capture_pre_process(struct context *ctx, snd_pcm_access_t *access,
 	unsigned int samples_per_frame = 0;
 	unsigned int frames_per_second = 0;
 	unsigned int channels;
-	int i;
+	unsigned int i;
 	int err;
 
 	err = xfer_context_pre_process(&ctx->xfer, &sample_format,
@@ -233,7 +233,7 @@ static int playback_pre_process(struct context *ctx, snd_pcm_access_t *access,
 	snd_pcm_format_t sample_format = SND_PCM_FORMAT_UNKNOWN;
 	unsigned int samples_per_frame = 0;
 	unsigned int frames_per_second = 0;
-	int i;
+	unsigned int i;
 	int err;
 
 	// Prepare for containers.
@@ -374,7 +374,7 @@ static int context_process_frames(struct context *ctx,
 {
 	bool verbose = ctx->xfer.verbose > 2;
 	unsigned int frame_count;
-	int i;
+	unsigned int i;
 	int err = 0;
 
 	if (!ctx->xfer.quiet) {
@@ -439,10 +439,10 @@ static int context_process_frames(struct context *ctx,
 }
 
 static void context_post_process(struct context *ctx,
-				 uint64_t accumulated_frame_count)
+				 uint64_t)
 {
 	uint64_t total_frame_count;
-	int i;
+	unsigned int i;
 
 	xfer_context_post_process(&ctx->xfer);
 
@@ -472,7 +472,7 @@ static void context_destroy(struct context *ctx)
 
 int subcmd_transfer(int argc, char *const *argv, snd_pcm_stream_t direction)
 {
-	struct context ctx = {0};
+	static struct context ctx = {0};
 	uint64_t expected_frame_count = 0;
 	uint64_t actual_frame_count = 0;
 	int err = 0;
diff --git a/axfer/waiter-epoll.c b/axfer/waiter-epoll.c
index 8f084f1..c09641b 100644
--- a/axfer/waiter-epoll.c
+++ b/axfer/waiter-epoll.c
@@ -36,7 +36,7 @@ static int epoll_prepare(struct waiter_context *waiter)
 	if (state->epfd < 0)
 		return -errno;
 
-	for (i = 0; i < waiter->pfd_count; ++i) {
+	for (i = 0; i < (int)waiter->pfd_count; ++i) {
 		struct epoll_event ev = {
 			.data.fd = waiter->pfds[i].fd,
 			.events = waiter->pfds[i].events,
@@ -64,9 +64,9 @@ static int epoll_wait_event(struct waiter_context *waiter, int timeout_msec)
 
 	if (ev_count > 0) {
 		// Reconstruct data of pollfd structure.
-		for (i = 0; i < ev_count; ++i) {
+		for (i = 0; i < (int)ev_count; ++i) {
 			struct epoll_event *ev = &state->events[i];
-			for (j = 0; j < waiter->pfd_count; ++j) {
+			for (j = 0; j < (int)waiter->pfd_count; ++j) {
 				if (waiter->pfds[i].fd == ev->data.fd) {
 					waiter->pfds[i].revents = ev->events;
 					break;
@@ -83,7 +83,7 @@ static void epoll_release(struct waiter_context *waiter)
 	struct epoll_state *state = waiter->private_data;
 	int i;
 
-	for (i = 0; i < waiter->pfd_count; ++i) {
+	for (i = 0; i < (int)waiter->pfd_count; ++i) {
 		int fd = waiter->pfds[i].fd;
 		epoll_ctl(state->epfd, EPOLL_CTL_DEL, fd, NULL);
 	}
diff --git a/axfer/waiter-poll.c b/axfer/waiter-poll.c
index 61aa1a0..31fab88 100644
--- a/axfer/waiter-poll.c
+++ b/axfer/waiter-poll.c
@@ -13,7 +13,7 @@
 #include <errno.h>
 #include <poll.h>
 
-static int poll_prepare(struct waiter_context *waiter)
+static int poll_prepare(struct waiter_context *)
 {
 	// Nothing to do because an instance of waiter has required data.
 	return 0;
@@ -30,7 +30,7 @@ static int poll_wait_event(struct waiter_context *waiter, int timeout_msec)
 	return err;
 }
 
-static void poll_release(struct waiter_context *waiter)
+static void poll_release(struct waiter_context *)
 {
 	// Nothing to do because an instance of waiter has required data.
 	return;
diff --git a/axfer/waiter-select.c b/axfer/waiter-select.c
index 97b1e5a..164c9c8 100644
--- a/axfer/waiter-select.c
+++ b/axfer/waiter-select.c
@@ -34,7 +34,7 @@ struct select_state {
 	fd_set rfds_ex;
 };
 
-static int select_prepare(struct waiter_context *waiter)
+static int select_prepare(struct waiter_context *)
 {
 	return 0;
 }
@@ -53,7 +53,7 @@ static int select_wait_event(struct waiter_context *waiter, int timeout_msec)
 	FD_ZERO(&state->rfds_ex);
 
 	fd_max = 0;
-	for (i = 0; i < waiter->pfd_count; ++i) {
+	for (i = 0; i < (int)waiter->pfd_count; ++i) {
 		pfd = &waiter->pfds[i];
 
 		if (pfd->events & POLLIN_SET)
@@ -79,7 +79,7 @@ static int select_wait_event(struct waiter_context *waiter, int timeout_msec)
 	if (err < 0)
 		return -errno;
 
-	for (i = 0; i < waiter->pfd_count; ++i) {
+	for (i = 0; i < (int)waiter->pfd_count; ++i) {
 		pfd = &waiter->pfds[i];
 
 		pfd->revents = 0;
@@ -94,7 +94,7 @@ static int select_wait_event(struct waiter_context *waiter, int timeout_msec)
 	return err;
 }
 
-static void select_release(struct waiter_context *waiter)
+static void select_release(struct waiter_context *)
 {
 	return;
 }
diff --git a/axfer/waiter.c b/axfer/waiter.c
index 1e9c811..dcca028 100644
--- a/axfer/waiter.c
+++ b/axfer/waiter.c
@@ -25,7 +25,7 @@ enum waiter_type waiter_type_from_label(const char *label)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(waiter_type_labels); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(waiter_type_labels); ++i) {
 		if (!strcmp(waiter_type_labels[i], label))
 			return i;
 	}
@@ -54,7 +54,7 @@ int waiter_context_init(struct waiter_context *waiter,
 	if (pfd_count == 0)
 		return -EINVAL;
 
-	for (i = 0; i < ARRAY_SIZE(entries); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(entries); ++i) {
 		if (entries[i].type == type)
 			break;
 	}
diff --git a/axfer/xfer-libasound-irq-mmap.c b/axfer/xfer-libasound-irq-mmap.c
index 386e741..382ef92 100644
--- a/axfer/xfer-libasound-irq-mmap.c
+++ b/axfer/xfer-libasound-irq-mmap.c
@@ -53,7 +53,7 @@ static int irq_mmap_pre_process(struct libasound_state *state)
 			return err;
 
 		logging(state, "attributes for mapped page frame:\n");
-		for (i = 0; i < layout->samples_per_frame; ++i) {
+		for (i = 0; i < (int)layout->samples_per_frame; ++i) {
 			const snd_pcm_channel_area_t *area = areas + i;
 
 			logging(state, "  sample number: %d\n", i);
@@ -152,7 +152,7 @@ static int irq_mmap_process_frames(struct libasound_state *state,
 		frame_buf = buf;
 	} else {
 		int i;
-		for (i = 0; i < layout->samples_per_frame; ++i) {
+		for (i = 0; i < (int)layout->samples_per_frame; ++i) {
 			layout->vector[i] = areas[i].addr;
 			layout->vector[i] += snd_pcm_samples_to_bytes(
 						state->handle, frame_offset);
diff --git a/axfer/xfer-libasound-irq-rw.c b/axfer/xfer-libasound-irq-rw.c
index 6ed1927..b7f0645 100644
--- a/axfer/xfer-libasound-irq-rw.c
+++ b/axfer/xfer-libasound-irq-rw.c
@@ -313,7 +313,7 @@ error:
 }
 
 static int w_process_frames_nonblocking(struct libasound_state *state,
-					snd_pcm_state_t status,
+					snd_pcm_state_t,
 					unsigned int *frame_count,
 					struct mapper_context *mapper,
 					struct container_context *cntrs)
diff --git a/axfer/xfer-libasound-timer-mmap.c b/axfer/xfer-libasound-timer-mmap.c
index 5715144..cbe5c97 100644
--- a/axfer/xfer-libasound-timer-mmap.c
+++ b/axfer/xfer-libasound-timer-mmap.c
@@ -78,7 +78,7 @@ static int timer_mmap_pre_process(struct libasound_state *state)
 			return err;
 
 		logging(state, "attributes for mapped page frame:\n");
-		for (i = 0; i < layout->samples_per_frame; ++i) {
+		for (i = 0; i < (int)layout->samples_per_frame; ++i) {
 			const snd_pcm_channel_area_t *area = areas + i;
 
 			logging(state, "  sample number: %d\n", i);
@@ -105,7 +105,7 @@ static void *get_buffer(struct libasound_state *state,
 		frame_buf = buf;
 	} else {
 		int i;
-		for (i = 0; i < layout->samples_per_frame; ++i) {
+		for (i = 0; i < (int)layout->samples_per_frame; ++i) {
 			layout->vector[i] = areas[i].addr;
 			layout->vector[i] += snd_pcm_samples_to_bytes(
 						state->handle, frame_offset);
@@ -188,7 +188,7 @@ static int timer_mmap_process_frames(struct libasound_state *state,
 		avail = snd_pcm_avail(state->handle);
 		if (avail < 0)
 			return (int)avail;
-		if (avail < planned_count) {
+		if (avail < (snd_pcm_sframes_t)planned_count) {
 			logging(state,
 				"Wake up but not enough space: %lu %lu %u\n",
 				planned_count, avail, timeout_msec);
diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c
index 00ff028..9713533 100644
--- a/axfer/xfer-libasound.c
+++ b/axfer/xfer-libasound.c
@@ -60,7 +60,7 @@ static const struct option l_opts[] = {
 };
 
 static int xfer_libasound_init(struct xfer_context *xfer,
-			       snd_pcm_stream_t direction)
+			       snd_pcm_stream_t)
 {
 	struct libasound_state *state = xfer->private_data;
 	int err;
@@ -887,7 +887,7 @@ static void xfer_libasound_destroy(struct xfer_context *xfer)
 	state->log = NULL;
 }
 
-static void xfer_libasound_help(struct xfer_context *xfer)
+static void xfer_libasound_help(struct xfer_context *)
 {
 	printf(
 "      [BASICS]\n"
diff --git a/axfer/xfer-options.c b/axfer/xfer-options.c
index 3740b16..974570c 100644
--- a/axfer/xfer-options.c
+++ b/axfer/xfer-options.c
@@ -53,7 +53,7 @@ static int allocate_paths(struct xfer_context *xfer, char *const *paths,
 			   unsigned int count)
 {
 	bool stdio = false;
-	int i;
+	unsigned int i;
 
 	if (count == 0) {
 		stdio = true;
@@ -66,7 +66,7 @@ static int allocate_paths(struct xfer_context *xfer, char *const *paths,
 	xfer->path_count = count;
 
 	if (stdio) {
-		xfer->paths[0] = strndup("-", PATH_MAX);
+		xfer->paths[0] = strdup("-");
 		if (xfer->paths[0] == NULL)
 			return -ENOMEM;
 	} else {
@@ -94,7 +94,7 @@ static int verify_cntr_format(struct xfer_context *xfer)
 	};
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(entries); ++i) {
+	for (i = 0; i < (int)ARRAY_SIZE(entries); ++i) {
 		entry = &entries[i];
 		if (strcasecmp(xfer->cntr_format_literal, entry->literal))
 			continue;
@@ -123,7 +123,7 @@ static int verify_sample_format(struct xfer_context *xfer)
 		{"cdr",	44100, 2, SND_PCM_FORMAT_S16_LE, SND_PCM_FORMAT_S16_BE},
 		{"dat",	48000, 2, SND_PCM_FORMAT_S16_LE, SND_PCM_FORMAT_S16_BE},
 	};
-	int i;
+	unsigned int i;
 
 	xfer->sample_format = snd_pcm_format_value(xfer->sample_format_literal);
 	if (xfer->sample_format != SND_PCM_FORMAT_UNKNOWN)
@@ -447,7 +447,7 @@ static int generate_path_with_suffix(struct xfer_context *xfer,
 
 static int generate_path_without_suffix(struct xfer_context *xfer,
 				        const char *template,
-					unsigned int index, const char *suffix)
+					unsigned int index, const char *)
 {
 	static const char *const single_format = "%s";
 	static const char *const multiple_format = "%s-%i";
@@ -498,7 +498,7 @@ static int create_paths(struct xfer_context *xfer, unsigned int path_count)
 {
 	char *template;
 	const char *suffix;
-	int i, j;
+	unsigned int i, j;
 	int err = 0;
 
 	// Can cause memory leak.
@@ -545,7 +545,7 @@ static int fixup_paths(struct xfer_context *xfer)
 {
 	const char *suffix;
 	char *template;
-	int i, j;
+	unsigned int i, j;
 	int err = 0;
 
 	suffix = container_suffix_from_format(xfer->cntr_format);
@@ -572,7 +572,7 @@ static int fixup_paths(struct xfer_context *xfer)
 
 int xfer_options_fixup_paths(struct xfer_context *xfer)
 {
-	int i, j;
+	unsigned int i, j;
 	int err;
 
 	if (xfer->path_count == 1) {
diff --git a/axfer/xfer.c b/axfer/xfer.c
index 6682b3b..3750e8a 100644
--- a/axfer/xfer.c
+++ b/axfer/xfer.c
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0
+
 //
 // xfer.c - receiver/transmiter of data frames.
 //
@@ -20,7 +20,7 @@ static const char *const xfer_type_labels[] = {
 
 enum xfer_type xfer_type_from_label(const char *label)
 {
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(xfer_type_labels); ++i) {
 		if (!strcmp(xfer_type_labels[i], label))
@@ -47,7 +47,7 @@ int xfer_context_init(struct xfer_context *xfer, enum xfer_type type,
 		{XFER_TYPE_LIBFFADO, &xfer_libffado},
 #endif
 	};
-	int i;
+	unsigned int i;
 	int err;
 
 	assert(xfer);
@@ -84,7 +84,7 @@ int xfer_context_init(struct xfer_context *xfer, enum xfer_type type,
 
 void xfer_context_destroy(struct xfer_context *xfer)
 {
-	int i;
+	unsigned int i;
 
 	assert(xfer);