diff --git a/janus/src/audio.c b/janus/src/audio.c
index 146a00d7..ec33c217 100644
--- a/janus/src/audio.c
+++ b/janus/src/audio.c
@@ -32,6 +32,7 @@
 #include <opus/opus.h>
 
 #include "uslibs/types.h"
+#include "uslibs/errors.h"
 #include "uslibs/tools.h"
 #include "uslibs/array.h"
 #include "uslibs/ring.h"
@@ -185,12 +186,12 @@ int us_audio_get_encoded(us_audio_s *audio, u8 *data, uz *size, u64 *pts) {
 	}
 	const int ri = us_ring_consumer_acquire(audio->enc_ring, 0.1);
 	if (ri < 0) {
-		return -2;
+		return US_ERROR_NO_DATA;
 	}
 	const _enc_buffer_s *const buf = audio->enc_ring->items[ri];
 	if (*size < buf->used) {
 		us_ring_consumer_release(audio->enc_ring, ri);
-		return -3;
+		return US_ERROR_NO_DATA;
 	}
 	memcpy(data, buf->data, buf->used);
 	*size = buf->used;
diff --git a/janus/src/memsinkfd.c b/janus/src/memsinkfd.c
index 0157c262..9730863e 100644
--- a/janus/src/memsinkfd.c
+++ b/janus/src/memsinkfd.c
@@ -27,6 +27,7 @@
 #include <linux/videodev2.h>
 
 #include "uslibs/types.h"
+#include "uslibs/errors.h"
 #include "uslibs/tools.h"
 #include "uslibs/frame.h"
 #include "uslibs/memsinksh.h"
@@ -54,7 +55,7 @@ int us_memsink_fd_wait_frame(int fd, us_memsink_shared_s *mem, u64 last_id) {
 		}
 		usleep(1000); // lock_polling
 	} while (now_ts < deadline_ts);
-	return -2;
+	return US_ERROR_NO_DATA;
 }
 
 int us_memsink_fd_get_frame(int fd, us_memsink_shared_s *mem, us_frame_s *frame, u64 *frame_id, bool key_required) {
diff --git a/janus/src/plugin.c b/janus/src/plugin.c
index e3492d75..703340f5 100644
--- a/janus/src/plugin.c
+++ b/janus/src/plugin.c
@@ -37,6 +37,7 @@
 
 #include "uslibs/types.h"
 #include "uslibs/const.h"
+#include "uslibs/errors.h"
 #include "uslibs/tools.h"
 #include "uslibs/threading.h"
 #include "uslibs/list.h"
@@ -178,7 +179,7 @@ static void *_video_sink_thread(void *arg) {
 				if (ri >= 0 && frame->key) {
 					atomic_store(&_g_key_required, false);
 				}
-			} else if (waited != -2) {
+			} else if (waited != US_ERROR_NO_DATA) {
 				goto close_memsink;
 			}
 		}
diff --git a/janus/src/uslibs/errors.h b/janus/src/uslibs/errors.h
new file mode 120000
index 00000000..5bf1521c
--- /dev/null
+++ b/janus/src/uslibs/errors.h
@@ -0,0 +1 @@
+../../../src/libs/errors.h
\ No newline at end of file
diff --git a/python/src/uslibs/errors.h b/python/src/uslibs/errors.h
new file mode 120000
index 00000000..5bf1521c
--- /dev/null
+++ b/python/src/uslibs/errors.h
@@ -0,0 +1 @@
+../../../src/libs/errors.h
\ No newline at end of file
diff --git a/python/src/ustreamer.c b/python/src/ustreamer.c
index 068cea53..dc620b27 100644
--- a/python/src/ustreamer.c
+++ b/python/src/ustreamer.c
@@ -14,6 +14,7 @@
 #include <Python.h>
 
 #include "uslibs/types.h"
+#include "uslibs/errors.h"
 #include "uslibs/tools.h"
 #include "uslibs/frame.h"
 #include "uslibs/memsinksh.h"
@@ -175,9 +176,9 @@ static int _wait_frame(_MemsinkObject *self) {
 		if (PyErr_CheckSignals() < 0) {
 			return -1;
 		}
-
 	} while (now_ts < deadline_ts);
-	return -2;
+
+	return US_ERROR_NO_DATA;
 }
 
 static PyObject *_MemsinkObject_wait_frame(_MemsinkObject *self, PyObject *args, PyObject *kwargs) {
@@ -194,7 +195,7 @@ static PyObject *_MemsinkObject_wait_frame(_MemsinkObject *self, PyObject *args,
 
 	switch (_wait_frame(self)) {
 		case 0: break;
-		case -2: Py_RETURN_NONE;
+		case US_ERROR_NO_DATA: Py_RETURN_NONE;
 		default: return NULL;
 	}
 
diff --git a/src/dump/main.c b/src/dump/main.c
index 3c7fa377..1616379b 100644
--- a/src/dump/main.c
+++ b/src/dump/main.c
@@ -31,6 +31,7 @@
 #include <assert.h>
 
 #include "../libs/const.h"
+#include "../libs/errors.h"
 #include "../libs/tools.h"
 #include "../libs/logging.h"
 #include "../libs/frame.h"
@@ -234,8 +235,8 @@ static int _dump_sink(
 
 	while (!_g_stop) {
 		bool key_requested;
-		const int error = us_memsink_client_get(sink, frame, &key_requested, key_required);
-		if (error == 0) {
+		const int got = us_memsink_client_get(sink, frame, &key_requested, key_required);
+		if (got == 0) {
 			key_required = false;
 
 			const long double now = us_get_now_monotonic();
@@ -275,7 +276,7 @@ static int _dump_sink(
 			if (interval_us > 0) {
 				usleep(interval_us);
 			}
-		} else if (error == -2) {
+		} else if (got == US_ERROR_NO_DATA) {
 			usleep(1000);
 		} else {
 			goto error;
diff --git a/src/libs/capture.c b/src/libs/capture.c
index 6011316c..4c556f2e 100644
--- a/src/libs/capture.c
+++ b/src/libs/capture.c
@@ -41,6 +41,7 @@
 #include <linux/v4l2-controls.h>
 
 #include "types.h"
+#include "errors.h"
 #include "tools.h"
 #include "array.h"
 #include "logging.h"
@@ -179,7 +180,7 @@ int us_capture_open(us_capture_s *cap) {
 			run->open_error_reported = -errno; // Don't confuse it with __LINE__
 			US_LOG_PERROR("No access to capture device");
 		}
-		goto tmp_error;
+		goto error_no_device;
 	}
 
 	_LOG_DEBUG("Opening capture device ...");
@@ -197,7 +198,7 @@ int us_capture_open(us_capture_s *cap) {
 				run->open_error_reported = line;
 				_LOG_ERROR("No signal from source");
 			}
-			goto tmp_error;
+			goto error_no_signal;
 		}
 	}
 
@@ -241,9 +242,13 @@ int us_capture_open(us_capture_s *cap) {
 	_LOG_INFO("Capturing started");
 	return 0;
 
-tmp_error:
+error_no_device:
 	us_capture_close(cap);
-	return -2;
+	return US_ERROR_NO_DEVICE;
+
+error_no_signal:
+	us_capture_close(cap);
+	return US_ERROR_NO_DATA;
 
 error:
 	run->open_error_reported = 0;
@@ -305,7 +310,7 @@ int us_capture_hwbuf_grab(us_capture_s *cap, us_capture_hwbuf_s **hw) {
 	//     или эвент V4L2. Обработка эвентов более приоритетна, чем кадров.
 	//   - Если есть новые фреймы, то пропустить их все, пока не закончатся и вернуть
 	//     самый-самый свежий, содержащий при этом валидные данные.
-	//   - Если таковых не нашлось, вернуть -2.
+	//   - Если таковых не нашлось, вернуть US_ERROR_NO_DATA.
 	//   - Ошибка -1 возвращается при любых сбоях.
 
 	if (_capture_wait_buffer(cap) < 0) {
@@ -392,7 +397,7 @@ int us_capture_hwbuf_grab(us_capture_s *cap, us_capture_hwbuf_s **hw) {
 				if (buf_got) {
 					break; // Process any latest valid frame
 				} else if (broken) {
-					return -2; // If we have only broken frames on this capture session
+					return US_ERROR_NO_DATA; // If we have only broken frames on this capture session
 				}
 			}
 			_LOG_PERROR("Can't grab HW buffer");
diff --git a/src/libs/drm/drm.c b/src/libs/drm/drm.c
index 4d3e21a5..de560a31 100644
--- a/src/libs/drm/drm.c
+++ b/src/libs/drm/drm.c
@@ -38,6 +38,7 @@
 #include <libdrm/drm.h>
 
 #include "../types.h"
+#include "../errors.h"
 #include "../tools.h"
 #include "../logging.h"
 #include "../frame.h"
@@ -98,7 +99,7 @@ int us_drm_open(us_drm_s *drm, const us_capture_s *cap) {
 
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: goto unplugged;
+		case US_ERROR_NO_DEVICE: goto unplugged;
 		default: goto error;
 	}
 
@@ -143,7 +144,7 @@ int us_drm_open(us_drm_s *drm, const us_capture_s *cap) {
 	const uint hz = (stub > 0 ? 0 : cap->run->hz);
 	switch (_drm_find_sink(drm, width, height, hz)) {
 		case 0: break;
-		case -2: goto unplugged;
+		case US_ERROR_NO_DEVICE: goto unplugged;
 		default: goto error;
 	}
 	if ((stub == 0) && (width != run->mode.hdisplay || height < run->mode.vdisplay)) {
@@ -179,7 +180,7 @@ int us_drm_open(us_drm_s *drm, const us_capture_s *cap) {
 		run->unplugged_reported = true;
 	}
 	us_drm_close(drm);
-	return -2;
+	return US_ERROR_NO_DEVICE;
 }
 
 void us_drm_close(us_drm_s *drm) {
@@ -245,7 +246,7 @@ int us_drm_dpms_power_off(us_drm_s *drm) {
 	assert(drm->run->fd >= 0);
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: return 0; // Unplugged, nice
+		case US_ERROR_NO_DEVICE: return 0; // Unplugged, nice
 		// Во время переключения DPMS монитор моргает один раз состоянием disconnected,
 		// а потом почему-то снова оказывается connected. Так что просто считаем,
 		// что отсоединенный монитор на этом этапе - это нормально.
@@ -262,7 +263,7 @@ int us_drm_wait_for_vsync(us_drm_s *drm) {
 
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: return -2;
+		case US_ERROR_NO_DEVICE: return US_ERROR_NO_DEVICE;
 		default: return -1;
 	}
 	_drm_ensure_dpms_power(drm, true);
@@ -317,7 +318,7 @@ int us_drm_expose_stub(us_drm_s *drm, us_drm_stub_e stub, const us_capture_s *ca
 
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: return -2;
+		case US_ERROR_NO_DEVICE: return US_ERROR_NO_DEVICE;
 		default: return -1;
 	}
 	_drm_ensure_dpms_power(drm, true);
@@ -381,7 +382,7 @@ int us_drm_expose_dma(us_drm_s *drm, const us_capture_hwbuf_s *hw) {
 
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: return -2;
+		case US_ERROR_NO_DEVICE: return US_ERROR_NO_DEVICE;
 		default: return -1;
 	}
 	_drm_ensure_dpms_power(drm, true);
@@ -434,7 +435,7 @@ static int _drm_check_status(us_drm_s *drm) {
 		goto error;
 	}
 	_LOG_DEBUG("Current display status: %c", status_ch);
-	return (status_ch == 'd' ? -2 : 0);
+	return (status_ch == 'd' ? US_ERROR_NO_DEVICE : 0);
 
 error:
 	US_CLOSE_FD(run->status_fd);
@@ -613,7 +614,7 @@ static int _drm_find_sink(us_drm_s *drm, uint width, uint height, float hz) {
 
 unplugged:
 	drmModeFreeResources(res);
-	return -2;
+	return US_ERROR_NO_DEVICE;
 }
 
 static drmModeModeInfo *_find_best_mode(drmModeConnector *conn, uint width, uint height, float hz) {
diff --git a/src/libs/errors.h b/src/libs/errors.h
new file mode 100644
index 00000000..295c42b8
--- /dev/null
+++ b/src/libs/errors.h
@@ -0,0 +1,27 @@
+/*****************************************************************************
+#                                                                            #
+#    uStreamer - Lightweight and fast MJPEG-HTTP streamer.                   #
+#                                                                            #
+#    Copyright (C) 2018-2024  Maxim Devaev <mdevaev@gmail.com>               #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+*****************************************************************************/
+
+
+#pragma once
+
+#define US_ERROR_COMMON		-1
+#define US_ERROR_NO_DEVICE	-2
+#define US_ERROR_NO_DATA	-3
diff --git a/src/libs/memsink.c b/src/libs/memsink.c
index 3ae63464..d2aa1520 100644
--- a/src/libs/memsink.c
+++ b/src/libs/memsink.c
@@ -33,6 +33,7 @@
 #include <sys/mman.h>
 
 #include "types.h"
+#include "errors.h"
 #include "tools.h"
 #include "logging.h"
 #include "frame.h"
@@ -168,7 +169,7 @@ int us_memsink_server_put(us_memsink_s *sink, const us_frame_s *frame, bool *key
 	if (frame->used > sink->data_size) {
 		US_LOG_ERROR("%s-sink: Can't put frame: is too big (%zu > %zu)",
 			sink->name, frame->used, sink->data_size);
-		return 0; // -2
+		return 0;
 	}
 
 	if (us_flock_timedwait_monotonic(sink->fd, 1) == 0) {
@@ -213,7 +214,7 @@ int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame, bool *key_reque
 
 	if (us_flock_timedwait_monotonic(sink->fd, sink->timeout) < 0) {
 		if (errno == EWOULDBLOCK) {
-			return -2;
+			return US_ERROR_NO_DATA;
 		}
 		US_LOG_PERROR("%s-sink: Can't lock memory", sink->name);
 		return -1;
@@ -222,7 +223,7 @@ int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame, bool *key_reque
 	int retval = 0;
 
 	if (sink->mem->magic != US_MEMSINK_MAGIC) {
-		retval = -2; // Not updated
+		retval = US_ERROR_NO_DATA; // Not updated
 		goto done;
 	}
 	if (sink->mem->version != US_MEMSINK_VERSION) {
@@ -236,7 +237,7 @@ int us_memsink_client_get(us_memsink_s *sink, us_frame_s *frame, bool *key_reque
 	sink->mem->last_client_ts = us_get_now_monotonic();
 
 	if (sink->mem->id == sink->last_readed_id) {
-		retval = -2; // Not updated
+		retval = US_ERROR_NO_DATA; // Not updated
 		goto done;
 	}
 
diff --git a/src/libs/tc358743.c b/src/libs/tc358743.c
index d0f6746b..3adccb85 100644
--- a/src/libs/tc358743.c
+++ b/src/libs/tc358743.c
@@ -58,7 +58,7 @@ int us_tc358743_xioctl_get_audio_hz(int fd, uint *audio_hz) {
 	US_MEMSET_ZERO(ctl);
 	ctl.id = TC358743_CID_AUDIO_SAMPLING_RATE;
 	if (us_xioctl(fd, VIDIOC_G_CTRL, &ctl) < 0) {
-		return -2;
+		return -1;
 	}
 	*audio_hz = ctl.value;
 	return 0;
diff --git a/src/ustreamer/stream.c b/src/ustreamer/stream.c
index f71fba7f..3675a153 100644
--- a/src/ustreamer/stream.c
+++ b/src/ustreamer/stream.c
@@ -24,6 +24,7 @@
 
 #include <stdlib.h>
 #include <stdatomic.h>
+#include <limits.h>
 #include <unistd.h>
 #include <errno.h>
 #include <assert.h>
@@ -31,6 +32,7 @@
 #include <pthread.h>
 
 #include "../libs/types.h"
+#include "../libs/errors.h"
 #include "../libs/tools.h"
 #include "../libs/threading.h"
 #include "../libs/process.h"
@@ -205,9 +207,9 @@ void us_stream_loop(us_stream_s *stream) {
 		while (!atomic_load(&run->stop) && !atomic_load(&threads_stop)) {
 			us_capture_hwbuf_s *hw;
 			switch (us_capture_hwbuf_grab(cap, &hw)) {
-				case -2: continue; // Broken frame
-				case -1: goto close; // Error
-				default: break; // Grabbed on >= 0
+				case 0 ... INT_MAX: break; // Grabbed buffer number
+				case US_ERROR_NO_DATA: continue; // Broken frame
+				default: goto close; // Any error
 			}
 
 			const sll now_sec_ts = us_floor_ms(us_get_now_monotonic());
@@ -600,7 +602,9 @@ static int _stream_init_loop(us_stream_s *stream) {
 			|| run->h264 != NULL
 		);
 		switch (us_capture_open(stream->cap)) {
-			case -2:
+			case 0: break;
+			case US_ERROR_NO_DEVICE:
+			case US_ERROR_NO_DATA:
 				if (!waiting_reported) {
 					waiting_reported = true;
 					US_LOG_INFO("Waiting for the capture device ...");
@@ -609,13 +613,12 @@ static int _stream_init_loop(us_stream_s *stream) {
 				_stream_drm_ensure_no_signal(stream);
 #				endif
 				goto offline_and_retry;
-			case -1:
+			default:
 				waiting_reported = false;
 #				ifdef WITH_V4P
 				_stream_drm_ensure_no_signal(stream);
 #				endif
 				goto offline_and_retry;
-			default: break;
 		}
 		us_encoder_open(stream->enc, stream->cap);
 		return 0;
diff --git a/src/v4p/main.c b/src/v4p/main.c
index 4e3a8dfa..24294781 100644
--- a/src/v4p/main.c
+++ b/src/v4p/main.c
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdatomic.h>
+#include <limits.h>
 #include <string.h>
 #include <unistd.h>
 #include <getopt.h>
@@ -36,6 +37,7 @@
 #include <sys/stat.h>
 
 #include "../libs/types.h"
+#include "../libs/errors.h"
 #include "../libs/const.h"
 #include "../libs/tools.h"
 #include "../libs/logging.h"
@@ -227,9 +229,9 @@ static void _main_loop(void) {
 
 			us_capture_hwbuf_s *hw;
 			switch (us_capture_hwbuf_grab(cap, &hw)) {
-				case -2: continue; // Broken frame
-				case -1: goto close; // Any error
-				default: break; // Grabbed on >= 0
+				case 0 ... INT_MAX: break; // Grabbed buffer number
+				case US_ERROR_NO_DATA: continue; // Broken frame
+				default: goto close; // Any error
 			}
 
 			if (drm_opened == 0) {