diff --git a/CMakeLists.txt b/CMakeLists.txt
index bc34eaa..b5ed2d9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,7 +32,7 @@ set(LIBSOUNDIO_HEADERS
 )
 
 set(TEST_SOURCES
-    "${CMAKE_SOURCE_DIR}/test/unit_tests.c"
+    "${CMAKE_SOURCE_DIR}/test/unit_tests.cpp"
 )
 
 find_package(Threads)
diff --git a/example/list_devices.c b/example/list_devices.c
index 4d190a6..f542b2d 100644
--- a/example/list_devices.c
+++ b/example/list_devices.c
@@ -18,6 +18,35 @@ static int usage(char *exe) {
     return 1;
 }
 
+static void print_channel_layout(const struct SoundIoChannelLayout *layout) {
+    if (layout->name) {
+        fprintf(stderr, "%s", layout->name);
+    } else {
+        fprintf(stderr, "%s", soundio_get_channel_name(layout->channels[0]));
+        for (int i = 1; i < layout->channel_count; i += 1) {
+            fprintf(stderr, ", %s", soundio_get_channel_name(layout->channels[i]));
+        }
+    }
+
+}
+
+static void print_device(struct SoundIoDevice *device, bool is_default) {
+    const char *purpose_str;
+    const char *default_str;
+    if (soundio_device_purpose(device) == SoundIoDevicePurposeOutput) {
+        purpose_str = "playback";
+        default_str = is_default ? " (default)" : "";
+    } else {
+        purpose_str = "recording";
+        default_str = is_default ? " (default)" : "";
+    }
+    const char *description = soundio_device_description(device);
+    int sample_rate = soundio_device_sample_rate(device);
+    fprintf(stderr, "%s device: ", purpose_str);
+    print_channel_layout(soundio_device_channel_layout(device));
+    fprintf(stderr, " %d Hz %s%s\n", sample_rate, description, default_str);
+}
+
 static int list_devices(struct SoundIo *soundio) {
     int output_count = soundio_get_output_device_count(soundio);
     int input_count = soundio_get_input_device_count(soundio);
@@ -27,21 +56,12 @@ static int list_devices(struct SoundIo *soundio) {
 
     for (int i = 0; i < input_count; i += 1) {
         struct SoundIoDevice *device = soundio_get_input_device(soundio, i);
-        const char *purpose_str = "input";
-        const char *default_str = (i == default_input) ? " (default)" : "";
-        const char *description = soundio_device_description(device);
-        int sample_rate = soundio_device_sample_rate(device);
-        fprintf(stderr, "%s device: %d Hz %s%s\n", purpose_str, sample_rate, description, default_str);
+        print_device(device, default_input == i);
         soundio_device_unref(device);
     }
     for (int i = 0; i < output_count; i += 1) {
         struct SoundIoDevice *device = soundio_get_output_device(soundio, i);
-
-        const char *purpose_str = "output";
-        const char *default_str = (i == default_output) ? " (default)" : "";
-        const char *description = soundio_device_description(device);
-        int sample_rate = soundio_device_sample_rate(device);
-        fprintf(stderr, "%s device: %d Hz %s%s\n", purpose_str, sample_rate, description, default_str);
+        print_device(device, default_output == i);
         soundio_device_unref(device);
     }
 
diff --git a/src/dummy.cpp b/src/dummy.cpp
index fa53e53..5dd6ee3 100644
--- a/src/dummy.cpp
+++ b/src/dummy.cpp
@@ -7,9 +7,33 @@
 
 #include "dummy.hpp"
 #include "soundio.hpp"
+#include "dummy_ring_buffer.hpp"
+#include "os.hpp"
 
 #include <stdio.h>
 #include <string.h>
+#include <atomic>
+using std::atomic_flag;
+
+struct SoundIoOutputDeviceDummy {
+    struct SoundIoOsThread *thread;
+    struct SoundIoOsMutex *mutex;
+    struct SoundIoOsCond *cond;
+    atomic_flag abort_flag;
+    int buffer_size;
+    double period;
+    struct SoundIoDummyRingBuffer ring_buffer;
+};
+
+struct SoundIoInputDeviceDummy {
+    // TODO
+};
+
+struct SoundIoDummy {
+    SoundIoOsMutex *mutex;
+    SoundIoOsCond *cond;
+    bool devices_emitted;
+};
 
 static void playback_thread_run(void *arg) {
     SoundIoOutputDevice *output_device = (SoundIoOutputDevice *)arg;
@@ -55,11 +79,49 @@ static void recording_thread_run(void *arg) {
 */
 
 static void destroy_dummy(SoundIo *soundio) {
-    destroy(soundio->safe_devices_info);
-    soundio->safe_devices_info = nullptr;
+    SoundIoDummy *sid = (SoundIoDummy *)soundio->backend_data;
+    if (!sid)
+        return;
+
+    if (sid->cond)
+        soundio_os_cond_destroy(sid->cond);
+
+    if (sid->mutex)
+        soundio_os_mutex_destroy(sid->mutex);
+
+    if (soundio->safe_devices_info) {
+        for (int i = 0; i < soundio->safe_devices_info->input_devices.length; i += 1)
+            soundio_device_unref(soundio->safe_devices_info->input_devices.at(i));
+        for (int i = 0; i < soundio->safe_devices_info->output_devices.length; i += 1)
+            soundio_device_unref(soundio->safe_devices_info->output_devices.at(i));
+        destroy(soundio->safe_devices_info);
+        soundio->safe_devices_info = nullptr;
+    }
+
 }
 
-static void flush_events(SoundIo *soundio) { }
+static void flush_events(SoundIo *soundio) {
+    SoundIoDummy *sid = (SoundIoDummy *)soundio->backend_data;
+    if (sid->devices_emitted)
+        return;
+    sid->devices_emitted = true;
+    soundio->on_devices_change(soundio);
+}
+
+static void wait_events(SoundIo *soundio) {
+    SoundIoDummy *sid = (SoundIoDummy *)soundio->backend_data;
+    flush_events(soundio);
+    soundio_os_mutex_lock(sid->mutex);
+    soundio_os_cond_wait(sid->cond, sid->mutex);
+    soundio_os_mutex_unlock(sid->mutex);
+}
+
+static void wakeup(SoundIo *soundio) {
+    SoundIoDummy *sid = (SoundIoDummy *)soundio->backend_data;
+    soundio_os_mutex_lock(sid->mutex);
+    soundio_os_cond_signal(sid->cond);
+    soundio_os_mutex_unlock(sid->mutex);
+}
 
 static void refresh_devices(SoundIo *soundio) { }
 
@@ -201,6 +263,26 @@ static void input_device_clear_buffer_dummy(SoundIo *soundio,
 }
 
 int soundio_dummy_init(SoundIo *soundio) {
+    assert(!soundio->backend_data);
+    SoundIoDummy *sid = create<SoundIoDummy>();
+    if (!sid) {
+        destroy_dummy(soundio);
+        return SoundIoErrorNoMem;
+    }
+    soundio->backend_data = sid;
+
+    sid->mutex = soundio_os_mutex_create();
+    if (!sid->mutex) {
+        destroy_dummy(soundio);
+        return SoundIoErrorNoMem;
+    }
+
+    sid->cond = soundio_os_cond_create();
+    if (!sid->cond) {
+        destroy_dummy(soundio);
+        return SoundIoErrorNoMem;
+    }
+
     assert(!soundio->safe_devices_info);
     soundio->safe_devices_info = create<SoundIoDevicesInfo>();
     if (!soundio->safe_devices_info) {
@@ -214,8 +296,10 @@ int soundio_dummy_init(SoundIo *soundio) {
     // create output device
     {
         SoundIoDevice *device = create<SoundIoDevice>();
-        if (!device)
+        if (!device) {
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
+        }
 
         device->ref_count = 1;
         device->soundio = soundio;
@@ -224,6 +308,7 @@ int soundio_dummy_init(SoundIo *soundio) {
         if (!device->name || !device->description) {
             free(device->name);
             free(device->description);
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
         }
         device->channel_layout = *soundio_channel_layout_get_builtin(SoundIoChannelLayoutIdMono);
@@ -234,6 +319,7 @@ int soundio_dummy_init(SoundIo *soundio) {
 
         if (soundio->safe_devices_info->output_devices.append(device)) {
             soundio_device_unref(device);
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
         }
     }
@@ -241,8 +327,10 @@ int soundio_dummy_init(SoundIo *soundio) {
     // create input device
     {
         SoundIoDevice *device = create<SoundIoDevice>();
-        if (!device)
+        if (!device) {
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
+        }
 
         device->ref_count = 1;
         device->soundio = soundio;
@@ -251,6 +339,7 @@ int soundio_dummy_init(SoundIo *soundio) {
         if (!device->name || !device->description) {
             free(device->name);
             free(device->description);
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
         }
         device->channel_layout = *soundio_channel_layout_get_builtin(SoundIoChannelLayoutIdMono);
@@ -261,6 +350,7 @@ int soundio_dummy_init(SoundIo *soundio) {
 
         if (soundio->safe_devices_info->input_devices.append(device)) {
             soundio_device_unref(device);
+            destroy_dummy(soundio);
             return SoundIoErrorNoMem;
         }
     }
@@ -268,6 +358,8 @@ int soundio_dummy_init(SoundIo *soundio) {
 
     soundio->destroy = destroy_dummy;
     soundio->flush_events = flush_events;
+    soundio->wait_events = wait_events;
+    soundio->wakeup = wakeup;
     soundio->refresh_devices = refresh_devices;
 
     soundio->output_device_init = output_device_init_dummy;
diff --git a/src/dummy.hpp b/src/dummy.hpp
index 5777976..603832e 100644
--- a/src/dummy.hpp
+++ b/src/dummy.hpp
@@ -8,27 +8,6 @@
 #ifndef SOUNDIO_DUMMY_HPP
 #define SOUNDIO_DUMMY_HPP
 
-#include "os.hpp"
-#include "dummy_ring_buffer.hpp"
-#include <atomic>
-using std::atomic_flag;
-
-struct SoundIoOutputDeviceDummy {
-    struct SoundIoOsThread *thread;
-    struct SoundIoOsMutex *mutex;
-    struct SoundIoOsCond *cond;
-    atomic_flag abort_flag;
-    int buffer_size;
-    double period;
-    struct SoundIoDummyRingBuffer ring_buffer;
-};
-
-struct SoundIoInputDeviceDummy {
-    // TODO
-};
-
 int soundio_dummy_init(struct SoundIo *soundio);
 
 #endif
-
-
diff --git a/src/list.hpp b/src/list.hpp
index 8c9ecfe..fc0da0d 100644
--- a/src/list.hpp
+++ b/src/list.hpp
@@ -70,49 +70,6 @@ struct SoundIoList {
         return 0;
     }
 
-    T swap_remove(int index) {
-        assert(index >= 0);
-        assert(index < length);
-        if (index == length - 1)
-            return pop();
-
-        T last = pop();
-        T item = items[index];
-        items[index] = last;
-        return item;
-    }
-
-    void remove_range(int start, int end) {
-        assert(0 <= start);
-        assert(start <= end);
-        assert(end <= length);
-        int del_count = end - start;
-        for (int i = start; i < length - del_count; i += 1) {
-            items[i] = items[i + del_count];
-        }
-        length -= del_count;
-    }
-
-    int __attribute__((warn_unused_result)) insert_space(int pos, int size) {
-        int old_length = length;
-        assert(pos >= 0 && pos <= old_length);
-        int err = resize(old_length + size);
-        if (err)
-            return err;
-
-        for (int i = old_length - 1; i >= pos; i -= 1) {
-            items[i + size] = items[i];
-        }
-
-        return 0;
-    }
-
-    void fill(T value) {
-        for (int i = 0; i < length; i += 1) {
-            items[i] = value;
-        }
-    }
-
     void clear() {
         length = 0;
     }
@@ -131,10 +88,6 @@ struct SoundIoList {
         return 0;
     }
 
-    int allocated_size() const {
-        return capacity * sizeof(T);
-    }
-
     T * items;
     int length;
     int capacity;
diff --git a/src/os.cpp b/src/os.cpp
index 76322f2..ebfef8e 100644
--- a/src/os.cpp
+++ b/src/os.cpp
@@ -249,3 +249,13 @@ void soundio_os_cond_timed_wait(struct SoundIoOsCond *cond,
         assert(err != EINVAL);
     }
 }
+
+void soundio_os_cond_wait(struct SoundIoOsCond *cond,
+        struct SoundIoOsMutex *mutex)
+{
+    int err;
+    if ((err = pthread_cond_wait(&cond->id, &mutex->id))) {
+        assert(err != EPERM);
+        assert(err != EINVAL);
+    }
+}
diff --git a/src/os.hpp b/src/os.hpp
index c2a7ecc..b221e11 100644
--- a/src/os.hpp
+++ b/src/os.hpp
@@ -35,5 +35,7 @@ void soundio_os_cond_broadcast(struct SoundIoOsCond *cond);
 
 void soundio_os_cond_timed_wait(struct SoundIoOsCond *cond,
         struct SoundIoOsMutex *mutex, double seconds);
+void soundio_os_cond_wait(struct SoundIoOsCond *cond,
+        struct SoundIoOsMutex *mutex);
 
 #endif
diff --git a/src/pulseaudio.cpp b/src/pulseaudio.cpp
index e6d060d..41f7d99 100644
--- a/src/pulseaudio.cpp
+++ b/src/pulseaudio.cpp
@@ -4,6 +4,48 @@
 #include <string.h>
 #include <math.h>
 
+#include <pulse/pulseaudio.h>
+#include <atomic>
+using std::atomic_bool;
+
+struct SoundIoOutputDevicePulseAudio {
+    pa_stream *stream;
+    atomic_bool stream_ready;
+    pa_buffer_attr buffer_attr;
+};
+
+struct SoundIoInputDevicePulseAudio {
+    pa_stream *stream;
+    atomic_bool stream_ready;
+    pa_buffer_attr buffer_attr;
+};
+
+struct SoundIoPulseAudio {
+    bool connection_refused;
+
+    pa_context *pulse_context;
+    atomic_bool device_scan_queued;
+
+    // the one that we're working on building
+    struct SoundIoDevicesInfo *current_devices_info;
+    char * default_sink_name;
+    char * default_source_name;
+
+    // this one is ready to be read with flush_events. protected by mutex
+    struct SoundIoDevicesInfo *ready_devices_info;
+
+    bool have_sink_list;
+    bool have_source_list;
+    bool have_default_sink;
+
+    atomic_bool ready_flag;
+    atomic_bool have_devices_flag;
+
+    pa_threaded_mainloop *main_loop;
+    pa_proplist *props;
+};
+
+
 static void subscribe_callback(pa_context *context,
         pa_subscription_event_type_t event_bits, uint32_t index, void *userdata)
 {
@@ -87,6 +129,9 @@ static void destroy_ready_devices_info(SoundIo *soundio) {
 
 static void destroy_pa(SoundIo *soundio) {
     SoundIoPulseAudio *ah = (SoundIoPulseAudio *)soundio->backend_data;
+    if (!ah)
+        return;
+
     if (ah->main_loop)
         pa_threaded_mainloop_stop(ah->main_loop);
 
@@ -104,6 +149,9 @@ static void destroy_pa(SoundIo *soundio) {
 
     free(ah->default_sink_name);
     free(ah->default_source_name);
+
+    destroy(ah);
+    soundio->backend_data = nullptr;
 }
 
 static double usec_to_sec(pa_usec_t usec) {
@@ -797,7 +845,13 @@ static void refresh_devices(SoundIo *soundio) {
 }
 
 int soundio_pulseaudio_init(SoundIo *soundio) {
-    SoundIoPulseAudio *ah = (SoundIoPulseAudio *)soundio->backend_data;
+    assert(!soundio->backend_data);
+    SoundIoPulseAudio *ah = create<SoundIoPulseAudio>();
+    if (!ah) {
+        destroy_pa(soundio);
+        return SoundIoErrorNoMem;
+    }
+    soundio->backend_data = ah;
 
     ah->connection_refused = false;
     ah->device_scan_queued = false;
diff --git a/src/pulseaudio.hpp b/src/pulseaudio.hpp
index 9ca84a2..f1480f3 100644
--- a/src/pulseaudio.hpp
+++ b/src/pulseaudio.hpp
@@ -8,47 +8,6 @@
 #ifndef SOUNDIO_PULSEAUDIO_HPP
 #define SOUNDIO_PULSEAUDIO_HPP
 
-#include <pulse/pulseaudio.h>
-#include <atomic>
-using std::atomic_bool;
-
-struct SoundIoOutputDevicePulseAudio {
-    pa_stream *stream;
-    atomic_bool stream_ready;
-    pa_buffer_attr buffer_attr;
-};
-
-struct SoundIoInputDevicePulseAudio {
-    pa_stream *stream;
-    atomic_bool stream_ready;
-    pa_buffer_attr buffer_attr;
-};
-
-struct SoundIoPulseAudio {
-    bool connection_refused;
-
-    pa_context *pulse_context;
-    atomic_bool device_scan_queued;
-
-    // the one that we're working on building
-    struct SoundIoDevicesInfo *current_devices_info;
-    char * default_sink_name;
-    char * default_source_name;
-
-    // this one is ready to be read with flush_events. protected by mutex
-    struct SoundIoDevicesInfo *ready_devices_info;
-
-    bool have_sink_list;
-    bool have_source_list;
-    bool have_default_sink;
-
-    atomic_bool ready_flag;
-    atomic_bool have_devices_flag;
-
-    pa_threaded_mainloop *main_loop;
-    pa_proplist *props;
-};
-
 int soundio_pulseaudio_init(struct SoundIo *soundio);
 
 #endif
diff --git a/src/soundio.cpp b/src/soundio.cpp
index e89be11..b8b6bf5 100644
--- a/src/soundio.cpp
+++ b/src/soundio.cpp
@@ -10,6 +10,7 @@
 #include "dummy.hpp"
 #include "pulseaudio.hpp"
 
+#include <string.h>
 #include <assert.h>
 
 const char *soundio_error_string(int error) {
@@ -138,3 +139,85 @@ struct SoundIoDevice *soundio_get_output_device(struct SoundIo *soundio, int ind
     soundio_device_ref(device);
     return device;
 }
+
+void soundio_device_ref(struct SoundIoDevice *device);
+void soundio_device_unref(struct SoundIoDevice *device);
+
+// the name is the identifier for the device. UTF-8 encoded
+const char *soundio_device_name(const struct SoundIoDevice *device) {
+    return device->name;
+}
+
+// UTF-8 encoded
+const char *soundio_device_description(const struct SoundIoDevice *device) {
+    return device->description;
+}
+
+enum SoundIoDevicePurpose soundio_device_purpose(const struct SoundIoDevice *device) {
+    return device->purpose;
+}
+
+const struct SoundIoChannelLayout *soundio_device_channel_layout(const struct SoundIoDevice *device) {
+    return &device->channel_layout;
+}
+
+int soundio_device_sample_rate(const struct SoundIoDevice *device) {
+    return device->default_sample_rate;
+}
+
+void soundio_device_unref(struct SoundIoDevice *device) {
+    if (!device)
+        return;
+
+    device->ref_count -= 1;
+    assert(device->ref_count >= 0);
+
+    if (device->ref_count == 0) {
+        free(device->name);
+        free(device->description);
+        destroy(device);
+    }
+}
+
+void soundio_device_ref(struct SoundIoDevice *device) {
+    device->ref_count += 1;
+}
+
+void soundio_wait_events(struct SoundIo *soundio) {
+    soundio->wait_events(soundio);
+}
+
+void soundio_wakeup(struct SoundIo *soundio) {
+    soundio->wakeup(soundio);
+}
+
+void soundio_output_device_fill_with_silence(struct SoundIoOutputDevice *output_device) {
+    char *buffer;
+    int requested_frame_count = soundio_output_device_free_count(output_device);
+    while (requested_frame_count > 0) {
+        int frame_count = requested_frame_count;
+        soundio_output_device_begin_write(output_device, &buffer, &frame_count);
+        memset(buffer, 0, frame_count * output_device->bytes_per_frame);
+        soundio_output_device_write(output_device, buffer, frame_count);
+        requested_frame_count -= frame_count;
+    }
+}
+
+int soundio_output_device_free_count(struct SoundIoOutputDevice *output_device) {
+    SoundIo *soundio = output_device->device->soundio;
+    return soundio->output_device_free_count(soundio, output_device);
+}
+
+void soundio_output_device_begin_write(struct SoundIoOutputDevice *output_device,
+        char **data, int *frame_count)
+{
+    SoundIo *soundio = output_device->device->soundio;
+    soundio->output_device_begin_write(soundio, output_device, data, frame_count);
+}
+
+void soundio_output_device_write(struct SoundIoOutputDevice *output_device,
+        char *data, int frame_count)
+{
+    SoundIo *soundio = output_device->device->soundio;
+    soundio->output_device_write(soundio, output_device, data, frame_count);
+}
diff --git a/src/soundio.h b/src/soundio.h
index 4eadb99..001e071 100644
--- a/src/soundio.h
+++ b/src/soundio.h
@@ -156,6 +156,8 @@ struct SoundIo {
 
     void (*destroy)(struct SoundIo *);
     void (*flush_events)(struct SoundIo *);
+    void (*wait_events)(struct SoundIo *);
+    void (*wakeup)(struct SoundIo *);
     void (*refresh_devices)(struct SoundIo *);
 
     int (*output_device_init)(struct SoundIo *, struct SoundIoOutputDevice *);
diff --git a/test/unit_tests.c b/test/unit_tests.cpp
similarity index 100%
rename from test/unit_tests.c
rename to test/unit_tests.cpp