diff --git a/dsp/audio/audio.c b/dsp/audio/audio.c
index b81985ee0..f05a6a3b6 100644
--- a/dsp/audio/audio.c
+++ b/dsp/audio/audio.c
@@ -18,7 +18,9 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "dsp/audio/cosmoaudio/cosmoaudio.h"
 #include "dsp/audio/describe.h"
+#include "libc/calls/blockcancel.internal.h"
 #include "libc/calls/calls.h"
+#include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/struct/stat.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/dce.h"
@@ -201,7 +203,7 @@ static void *cosmoaudio_dlopen(const char *name) {
   return 0;
 }
 
-static void cosmoaudio_setup(void) {
+static void cosmoaudio_setup_impl(void) {
   void *handle;
   if (IsOpenbsd())
     return;  // no dlopen support yet
@@ -239,6 +241,12 @@ WeAreGood:
   g_audio.poll = cosmo_dlsym(handle, "cosmoaudio_poll");
 }
 
+static void cosmoaudio_setup(void) {
+  BLOCK_CANCELATION;
+  cosmoaudio_setup_impl();
+  ALLOW_CANCELATION;
+}
+
 static void cosmoaudio_init(void) {
   pthread_once(&g_audio.once, cosmoaudio_setup);
 }
@@ -249,10 +257,13 @@ COSMOAUDIO_ABI int cosmoaudio_open(
   char sbuf[32];
   char dbuf[256];
   cosmoaudio_init();
-  if (g_audio.open)
+  if (g_audio.open) {
+    BLOCK_SIGNALS;
     status = g_audio.open(out_ca, options);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   STRACE("cosmoaudio_open([%p], %s) → %s",
          out_ca ? *out_ca : (struct CosmoAudio *)-1,
          cosmoaudio_describe_open_options(dbuf, sizeof(dbuf), options),
@@ -263,10 +274,13 @@ COSMOAUDIO_ABI int cosmoaudio_open(
 COSMOAUDIO_ABI int cosmoaudio_close(struct CosmoAudio *ca) {
   int status;
   char sbuf[32];
-  if (g_audio.close)
+  if (g_audio.close) {
+    BLOCK_SIGNALS;
     status = g_audio.close(ca);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   STRACE("cosmoaudio_close(%p) → %s", ca,
          cosmoaudio_describe_status(sbuf, sizeof(sbuf), status));
   return status;
@@ -276,10 +290,13 @@ COSMOAUDIO_ABI int cosmoaudio_write(struct CosmoAudio *ca, const float *data,
                                     int frames) {
   int status;
   char sbuf[32];
-  if (g_audio.write)
+  if (g_audio.write) {
+    BLOCK_SIGNALS;
     status = g_audio.write(ca, data, frames);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   if (frames <= 0 || frames >= 160)
     DATATRACE("cosmoaudio_write(%p, %p, %d) → %s", ca, data, frames,
               cosmoaudio_describe_status(sbuf, sizeof(sbuf), status));
@@ -290,10 +307,13 @@ COSMOAUDIO_ABI int cosmoaudio_read(struct CosmoAudio *ca, float *data,
                                    int frames) {
   int status;
   char sbuf[32];
-  if (g_audio.read)
+  if (g_audio.read) {
+    BLOCK_SIGNALS;
     status = g_audio.read(ca, data, frames);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   if (frames <= 0 || frames >= 160)
     DATATRACE("cosmoaudio_read(%p, %p, %d) → %s", ca, data, frames,
               cosmoaudio_describe_status(sbuf, sizeof(sbuf), status));
@@ -303,10 +323,13 @@ COSMOAUDIO_ABI int cosmoaudio_read(struct CosmoAudio *ca, float *data,
 COSMOAUDIO_ABI int cosmoaudio_flush(struct CosmoAudio *ca) {
   int status;
   char sbuf[32];
-  if (g_audio.flush)
+  if (g_audio.flush) {
+    BLOCK_SIGNALS;
     status = g_audio.flush(ca);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   DATATRACE("cosmoaudio_flush(%p) → %s", ca,
             cosmoaudio_describe_status(sbuf, sizeof(sbuf), status));
   return status;
@@ -318,10 +341,13 @@ COSMOAUDIO_ABI int cosmoaudio_poll(struct CosmoAudio *ca,
   int status;
   char sbuf[32];
   char fbuf[2][20];
-  if (g_audio.poll)
+  if (g_audio.poll) {
+    BLOCK_SIGNALS;
     status = g_audio.poll(ca, in_out_readFrames, in_out_writeFrames);
-  else
+    ALLOW_SIGNALS;
+  } else {
     status = COSMOAUDIO_ELINK;
+  }
   DATATRACE("cosmoaudio_poll(%p, %s, %s) → %s", ca,
             cosmoaudio_describe_poll_frames(fbuf[0], sizeof(fbuf[0]),
                                             in_out_readFrames),
diff --git a/dsp/audio/cosmoaudio/cosmoaudio.c b/dsp/audio/cosmoaudio/cosmoaudio.c
index d09b7b69d..bff7d14cf 100644
--- a/dsp/audio/cosmoaudio/cosmoaudio.c
+++ b/dsp/audio/cosmoaudio/cosmoaudio.c
@@ -19,25 +19,19 @@
 #include <stdlib.h>
 #include <string.h>
 
-#define MA_STATIC
+#define MA_DEBUG_OUTPUT
+#define MA_DR_MP3_NO_STDIO
 #define MA_NO_DECODING
 #define MA_NO_ENCODING
 #define MA_NO_ENGINE
 #define MA_NO_GENERATION
 #define MA_NO_NODE_GRAPH
 #define MA_NO_RESOURCE_MANAGER
-#ifdef NDEBUG
-#define MA_DR_MP3_NO_STDIO
-#endif
+#define MA_STATIC
+
 #define MINIAUDIO_IMPLEMENTATION
 #include "miniaudio.h"
 
-#ifndef NDEBUG
-#define LOG(...) fprintf(stderr, __VA_ARGS__)
-#else
-#define LOG(...) (void)0
-#endif
-
 struct CosmoAudio {
   enum CosmoAudioDeviceType deviceType;
   ma_uint32 outputBufferFrames;
@@ -45,14 +39,16 @@ struct CosmoAudio {
   int sampleRate;
   int channels;
   int isLeft;
+  ma_context context;
   ma_device device;
   ma_pcm_rb output;
   ma_pcm_rb input;
   ma_event event;
+  ma_log log;
 };
 
-static int read_ring_buffer(ma_pcm_rb* rb, float* pOutput, ma_uint32 frameCount,
-                            ma_uint32 channels) {
+static int read_ring_buffer(ma_log* log, ma_pcm_rb* rb, float* pOutput,
+                            ma_uint32 frameCount, ma_uint32 channels) {
   ma_result result;
   ma_uint32 framesRead;
   ma_uint32 framesToRead;
@@ -61,7 +57,9 @@ static int read_ring_buffer(ma_pcm_rb* rb, float* pOutput, ma_uint32 frameCount,
     void* pMappedBuffer;
     result = ma_pcm_rb_acquire_read(rb, &framesToRead, &pMappedBuffer);
     if (result != MA_SUCCESS) {
-      LOG("ma_pcm_rb_acquire_read failed: %s\n", ma_result_description(result));
+      ma_log_postf(log, MA_LOG_LEVEL_WARNING,
+                   "ma_pcm_rb_acquire_read failed: %s\n",
+                   ma_result_description(result));
       return COSMOAUDIO_ERROR;
     }
     if (!framesToRead)
@@ -74,14 +72,16 @@ static int read_ring_buffer(ma_pcm_rb* rb, float* pOutput, ma_uint32 frameCount,
         framesRead += framesToRead;
         break;
       }
-      LOG("ma_pcm_rb_commit_read failed: %s\n", ma_result_description(result));
+      ma_log_postf(log, MA_LOG_LEVEL_WARNING,
+                   "ma_pcm_rb_commit_read failed: %s\n",
+                   ma_result_description(result));
       return COSMOAUDIO_ERROR;
     }
   }
   return framesRead;
 }
 
-static int write_ring_buffer(ma_pcm_rb* rb, const float* pInput,
+static int write_ring_buffer(ma_log* log, ma_pcm_rb* rb, const float* pInput,
                              ma_uint32 frameCount, ma_uint32 channels) {
   ma_result result;
   ma_uint32 framesWritten;
@@ -92,8 +92,9 @@ static int write_ring_buffer(ma_pcm_rb* rb, const float* pInput,
     void* pMappedBuffer;
     result = ma_pcm_rb_acquire_write(rb, &framesToWrite, &pMappedBuffer);
     if (result != MA_SUCCESS) {
-      LOG("ma_pcm_rb_acquire_write failed: %s\n",
-          ma_result_description(result));
+      ma_log_postf(log, MA_LOG_LEVEL_WARNING,
+                   "ma_pcm_rb_acquire_write failed: %s\n",
+                   ma_result_description(result));
       return COSMOAUDIO_ERROR;
     }
     if (!framesToWrite)
@@ -106,7 +107,9 @@ static int write_ring_buffer(ma_pcm_rb* rb, const float* pInput,
         framesWritten += framesToWrite;
         break;
       }
-      LOG("ma_pcm_rb_commit_write failed: %s\n", ma_result_description(result));
+      ma_log_postf(log, MA_LOG_LEVEL_WARNING,
+                   "ma_pcm_rb_commit_write failed: %s\n",
+                   ma_result_description(result));
       return COSMOAUDIO_ERROR;
     }
   }
@@ -126,8 +129,8 @@ static void data_callback_f32(ma_device* pDevice, float* pOutput,
     //          —Quoth miniaudio documentation § 16.1. Low Level API
     //
     if (ca->isLeft) {
-      int framesCopied =
-          read_ring_buffer(&ca->output, pOutput, frameCount, ca->channels);
+      int framesCopied = read_ring_buffer(&ca->log, &ca->output, pOutput,
+                                          frameCount, ca->channels);
       if (framesCopied < (int)frameCount)
         ca->isLeft = 0;
     } else {
@@ -140,13 +143,14 @@ static void data_callback_f32(ma_device* pDevice, float* pOutput,
         frameOffset = frameCount - availableFrames;
         frameCount = availableFrames;
       }
-      read_ring_buffer(&ca->output, pOutput + frameOffset * ca->channels,
-                       frameCount, ca->channels);
+      read_ring_buffer(&ca->log, &ca->output,
+                       pOutput + frameOffset * ca->channels, frameCount,
+                       ca->channels);
       ca->isLeft = 1;
     }
   }
   if (ca->deviceType & kCosmoAudioDeviceTypeCapture)
-    write_ring_buffer(&ca->input, pInput, frameCount, ca->channels);
+    write_ring_buffer(&ca->log, &ca->input, pInput, frameCount, ca->channels);
   ma_event_signal(&ca->event);
 }
 
@@ -211,6 +215,25 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
     return COSMOAUDIO_ERROR;
   }
 
+  // Create audio log.
+  if (ma_log_init(NULL, &ca->log) != MA_SUCCESS) {
+    ma_event_uninit(&ca->event);
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+  if (!options->debugLog)
+    ca->log.callbackCount = 0;
+
+  // Create audio context.
+  ma_context_config contextConfig = ma_context_config_init();
+  contextConfig.pLog = &ca->log;
+  if (ma_context_init(NULL, 0, &contextConfig, &ca->context) != MA_SUCCESS) {
+    ma_event_uninit(&ca->event);
+    ma_log_uninit(&ca->log);
+    free(ca);
+    return COSMOAUDIO_ERROR;
+  }
+
   // Initialize device.
   ma_result result;
   ma_device_config deviceConfig;
@@ -227,9 +250,11 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
   }
   deviceConfig.dataCallback = data_callback;
   deviceConfig.pUserData = ca;
-  result = ma_device_init(NULL, &deviceConfig, &ca->device);
+  result = ma_device_init(&ca->context, &deviceConfig, &ca->device);
   if (result != MA_SUCCESS) {
+    ma_context_uninit(&ca->context);
     ma_event_uninit(&ca->event);
+    ma_log_uninit(&ca->log);
     free(ca);
     return COSMOAUDIO_ERROR;
   }
@@ -248,7 +273,9 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
                             NULL, NULL, &ca->output);
     if (result != MA_SUCCESS) {
       ma_device_uninit(&ca->device);
+      ma_context_uninit(&ca->context);
       ma_event_uninit(&ca->event);
+      ma_log_uninit(&ca->log);
       free(ca);
       return COSMOAUDIO_ERROR;
     }
@@ -268,10 +295,12 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
     result = ma_pcm_rb_init(ma_format_f32, ca->channels, ca->inputBufferFrames,
                             NULL, NULL, &ca->input);
     if (result != MA_SUCCESS) {
+      ma_device_uninit(&ca->device);
       if (ca->deviceType & kCosmoAudioDeviceTypePlayback)
         ma_pcm_rb_uninit(&ca->output);
-      ma_device_uninit(&ca->device);
+      ma_context_uninit(&ca->context);
       ma_event_uninit(&ca->event);
+      ma_log_uninit(&ca->log);
       free(ca);
       return COSMOAUDIO_ERROR;
     }
@@ -280,12 +309,14 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
 
   // Start audio playback.
   if (ma_device_start(&ca->device) != MA_SUCCESS) {
+    ma_device_uninit(&ca->device);
     if (ca->deviceType & kCosmoAudioDeviceTypePlayback)
       ma_pcm_rb_uninit(&ca->output);
     if (ca->deviceType & kCosmoAudioDeviceTypeCapture)
       ma_pcm_rb_uninit(&ca->input);
-    ma_device_uninit(&ca->device);
+    ma_context_uninit(&ca->context);
     ma_event_uninit(&ca->event);
+    ma_log_uninit(&ca->log);
     free(ca);
     return COSMOAUDIO_ERROR;
   }
@@ -311,12 +342,14 @@ COSMOAUDIO_ABI int cosmoaudio_open(  //
 COSMOAUDIO_ABI int cosmoaudio_close(struct CosmoAudio* ca) {
   if (!ca)
     return COSMOAUDIO_EINVAL;
+  ma_device_uninit(&ca->device);  // do this first
   if (ca->deviceType & kCosmoAudioDeviceTypePlayback)
     ma_pcm_rb_uninit(&ca->output);
   if (ca->deviceType & kCosmoAudioDeviceTypeCapture)
     ma_pcm_rb_uninit(&ca->input);
-  ma_device_uninit(&ca->device);
+  ma_context_uninit(&ca->context);
   ma_event_uninit(&ca->event);
+  ma_log_uninit(&ca->log);
   free(ca);
   return COSMOAUDIO_SUCCESS;
 }
@@ -330,6 +363,12 @@ COSMOAUDIO_ABI int cosmoaudio_close(struct CosmoAudio* ca) {
  * repeatedly called at a regular time interval. The caller should
  * have its own sleep loop for this purpose.
  *
+ * This function never blocks. Programs that don't have their own timer
+ * can use cosmoaudio_poll() to wait until audio may be written.
+ *
+ * For any given CosmoAudio object, it's assumed that only a single
+ * thread will call this function.
+ *
  * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
  * @param data is pointer to raw audio samples, expected to be in the range
  *     -1.0 to 1.0, where channels are interleaved
@@ -351,17 +390,23 @@ COSMOAUDIO_ABI int cosmoaudio_write(struct CosmoAudio* ca, const float* data,
     return 0;
   if (!data)
     return COSMOAUDIO_EINVAL;
-  return write_ring_buffer(&ca->output, data, frames, ca->channels);
+  return write_ring_buffer(&ca->log, &ca->output, data, frames, ca->channels);
 }
 
 /**
  * Reads raw audio data from microphone.
  *
  * The data is read from a ring buffer in real-time, which is then
- * played back very soon on the audio device. This has tolerence for
- * a certain amount of buffering, but expects that this function is
- * repeatedly called at a regular time interval. The caller should
- * have its own sleep loop for this purpose.
+ * played back on the audio device. This has tolerence for a certain
+ * amount of buffering (based on the `bufferFrames` parameter passed to
+ * cosmoaudio_open(), which by default assumes this function will be
+ * called at at a regular time interval.
+ *
+ * This function never blocks. Programs that don't have their own timer
+ * can use cosmoaudio_poll() to wait until audio may be read.
+ *
+ * For any given CosmoAudio object, it's assumed that only a single
+ * thread will call this function.
  *
  * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
  * @param data is pointer to raw audio samples, expected to be in the range
@@ -382,11 +427,16 @@ COSMOAUDIO_ABI int cosmoaudio_read(struct CosmoAudio* ca, float* data,
     return 0;
   if (!data)
     return COSMOAUDIO_EINVAL;
-  return read_ring_buffer(&ca->input, data, frames, ca->channels);
+  return read_ring_buffer(&ca->log, &ca->input, data, frames, ca->channels);
 }
 
 /**
- * Waits for read and/or write to become possible.
+ * Waits until it's possible to read/write audio.
+ *
+ * This function is uninterruptible. All signals are masked throughout
+ * the duration of time this function may block, including cancelation
+ * signals, because this is not a cancelation point. Cosmopolitan Libc
+ * applies this masking in its dlopen wrapper.
  *
  * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
  * @param in_out_readFrames if non-NULL specifies how many frames of
@@ -447,6 +497,11 @@ COSMOAUDIO_ABI int cosmoaudio_poll(struct CosmoAudio* ca,
  *
  * This function is only valid to call in playback or duplex mode.
  *
+ * This function is uninterruptible. All signals are masked throughout
+ * the duration of time this function may block, including cancelation
+ * signals, because this is not a cancelation point. Cosmopolitan Libc
+ * applies this masking in its dlopen wrapper.
+ *
  * @param ca is CosmoAudio object returned earlier by cosmoaudio_open()
  * @return 0 on success, or negative error code on failure
  */
diff --git a/dsp/audio/cosmoaudio/cosmoaudio.dll b/dsp/audio/cosmoaudio/cosmoaudio.dll
index 4e4d1e863..7ef152aa4 100644
Binary files a/dsp/audio/cosmoaudio/cosmoaudio.dll and b/dsp/audio/cosmoaudio/cosmoaudio.dll differ
diff --git a/dsp/audio/cosmoaudio/cosmoaudio.h b/dsp/audio/cosmoaudio/cosmoaudio.h
index ce2bc48ce..40158ab81 100644
--- a/dsp/audio/cosmoaudio/cosmoaudio.h
+++ b/dsp/audio/cosmoaudio/cosmoaudio.h
@@ -59,6 +59,9 @@ struct CosmoAudioOpenOptions {
   // sample for each channel. Set to 0 for default. If this is less than
   // the device period size times two, it'll be increased to that value.
   int bufferFrames;
+
+  // Enables debug logging if non-zero.
+  int debugLog;
 };
 
 COSMOAUDIO_API int cosmoaudio_version(void) COSMOAUDIO_ABI;
diff --git a/dsp/audio/cosmoaudio/test.c b/dsp/audio/cosmoaudio/test.c
index b554d4da8..a6c7e2375 100644
--- a/dsp/audio/cosmoaudio/test.c
+++ b/dsp/audio/cosmoaudio/test.c
@@ -53,7 +53,7 @@ int main() {
       float t = (float)g++ / SAMPLING_RATE;
       float s = sinf(2 * M_PIf * WAVE_INTERVAL * t);
       for (int c = 0; c < CHANNELS; c++)
-        buf[f * CHANNELS + c] = s;
+        buf[f * CHANNELS + c] = s * .3f;
     }
     status = cosmoaudio_write(ca, buf, frames);
     if (status != frames) {
diff --git a/dsp/audio/describe.c b/dsp/audio/describe.c
index feb565bb4..71d6eb91d 100644
--- a/dsp/audio/describe.c
+++ b/dsp/audio/describe.c
@@ -90,6 +90,13 @@ const char *cosmoaudio_describe_open_options(
     gotsome = true;
   }
 
+  if (options->debugLog) {
+    if (gotsome)
+      append(", ");
+    append(".debugLog=%d", options->debugLog);
+    gotsome = true;
+  }
+
   if (options->sizeofThis) {
     if (gotsome)
       append(", ");
diff --git a/examples/a440.c b/examples/a440.c
new file mode 100644
index 000000000..3b927da7d
--- /dev/null
+++ b/examples/a440.c
@@ -0,0 +1,80 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include <cosmoaudio.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+/**
+ * @fileoverview plays pure A.440 tone on speakers for 1 second
+ * @see https://en.wikipedia.org/wiki/A440_%28pitch_standard%29
+ */
+
+#define SAMPLING_RATE 44100
+#define WAVE_INTERVAL 440
+#define CHANNELS      2
+#define LOUDNESS      .3
+#define DEBUG_LOG     1
+
+int main() {
+
+  struct CosmoAudioOpenOptions cao = {0};
+  cao.sizeofThis = sizeof(struct CosmoAudioOpenOptions);
+  cao.deviceType = kCosmoAudioDeviceTypePlayback;
+  cao.sampleRate = SAMPLING_RATE;
+  cao.debugLog = DEBUG_LOG;
+  cao.channels = CHANNELS;
+
+  int status;
+  struct CosmoAudio *ca;
+  status = cosmoaudio_open(&ca, &cao);
+  if (status != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "failed to open audio: %d\n", status);
+    return 1;
+  }
+
+  float buf[256 * CHANNELS];
+  for (int g = 0; g < SAMPLING_RATE;) {
+    int frames = 1;
+    status = cosmoaudio_poll(ca, NULL, &frames);
+    if (status != COSMOAUDIO_SUCCESS) {
+      fprintf(stderr, "failed to poll output: %d\n", status);
+      return 2;
+    }
+    if (frames > 256)
+      frames = 256;
+    if (frames > SAMPLING_RATE - g)
+      frames = SAMPLING_RATE - g;
+    for (int f = 0; f < frames; ++f) {
+      float t = (float)g++ / SAMPLING_RATE;
+      float s = sinf(2 * M_PIf * WAVE_INTERVAL * t);
+      for (int c = 0; c < CHANNELS; c++)
+        buf[f * CHANNELS + c] = s * LOUDNESS;
+    }
+    status = cosmoaudio_write(ca, buf, frames);
+    if (status != frames) {
+      fprintf(stderr, "failed to write output: %d\n", status);
+      return 3;
+    }
+  }
+
+  status = cosmoaudio_flush(ca);
+  if (status != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "failed to flush output: %d\n", status);
+    return 4;
+  }
+
+  status = cosmoaudio_close(ca);
+  if (status != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "failed to close audio: %d\n", status);
+    return 5;
+  }
+}
diff --git a/examples/blas.cc b/examples/blas.cc
index 70c32c451..1dbdec7cc 100644
--- a/examples/blas.cc
+++ b/examples/blas.cc
@@ -14,16 +14,16 @@
 // PERFORMANCE OF THIS SOFTWARE.
 
 #include <unistd.h>
+#include <cassert>
 #include <cinttypes>
 #include <cmath>
 #include <cstdio>
 #include <cstdlib>
 #include <ctime>
-#include "libc/assert.h"
 
 // high performance high accuracy matrix multiplication in ansi c
 
-#define MATH __target_clones("avx512f,fma")
+#define MATH __target_clones("avx512f,fma,avx")
 
 namespace {
 namespace ansiBLAS {
diff --git a/examples/clear.c b/examples/clear.c
index f008c5845..c03453e0e 100644
--- a/examples/clear.c
+++ b/examples/clear.c
@@ -7,7 +7,7 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
+#include <unistd.h>
 
 // clears teletypewriter display
 //
diff --git a/examples/crashreport.c b/examples/crashreport.c
index 4e41ebf7f..b8219d83c 100644
--- a/examples/crashreport.c
+++ b/examples/crashreport.c
@@ -7,12 +7,7 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/intrin/kprintf.h"
-#include "libc/math.h"
-#include "libc/runtime/runtime.h"
-#include "libc/runtime/symbols.internal.h"
-#include "libc/stdio/stdio.h"
+#include <cosmo.h>
 
 /**
  * @fileoverview How to print backtraces and cpu state on crash.
diff --git a/examples/date.c b/examples/date.c
index 7bfeaca5d..a0d3c6656 100644
--- a/examples/date.c
+++ b/examples/date.c
@@ -7,18 +7,11 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/timespec.h"
-#include "libc/intrin/kprintf.h"
-#include "libc/macros.h"
-#include "libc/nt/enum/timezoneid.h"
-#include "libc/nt/struct/timezoneinformation.h"
-#include "libc/nt/time.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/thread/threads.h"
-#include "libc/time.h"
+#include <stdlib.h>
+#include <string.h>
+#include <threads.h>
+#include <time.h>
+#include <unistd.h>
 
 /**
  * @fileoverview High performance ISO-8601 timestamp formatter.
@@ -27,6 +20,8 @@
  * Consider using something like this instead for your loggers.
  */
 
+#define ABS(X) ((X) >= 0 ? (X) : -(X))
+
 char *GetTimestamp(void) {
   int x;
   struct timespec ts;
diff --git a/examples/dlopen.c b/examples/dlopen.c
index 545513918..3198e5361 100644
--- a/examples/dlopen.c
+++ b/examples/dlopen.c
@@ -7,11 +7,9 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/dlopen/dlfcn.h"
-#include "libc/fmt/itoa.h"
-#include "libc/nt/thunk/msabi.h"
-#include "libc/runtime/runtime.h"
+#include <cosmo.h>
+#include <dlfcn.h>
+#include <stdlib.h>
 
 /**
  * @fileoverview cosmopolitan dynamic runtime linking demo
diff --git a/examples/env.c b/examples/env.c
index 5e607ddad..83973ddee 100644
--- a/examples/env.c
+++ b/examples/env.c
@@ -1,10 +1,21 @@
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+
+/**
+ * @fileoverview prints environment variables
+ */
 
 int main(int argc, char* argv[]) {
-  fprintf(stderr, "%s (%s)\n", argv[0], GetProgramExecutableName());
-  for (char** p = environ; *p; ++p) {
-    printf("%s\n", *p);
-  }
+  for (char** p = environ; *p; ++p)
+    puts(*p);
   return 0;
 }
diff --git a/examples/greenbean.c b/examples/greenbean.c
index 8ffc51622..fda9ae999 100644
--- a/examples/greenbean.c
+++ b/examples/greenbean.c
@@ -23,8 +23,6 @@
 #include <sys/auxv.h>
 #include <sys/socket.h>
 #include <time.h>
-#include "libc/mem/leaks.h"
-#include "libc/runtime/runtime.h"
 
 /**
  * @fileoverview greenbean lightweight threaded web server
diff --git a/examples/hangman.c b/examples/hangman.c
index 4aa736490..a739af289 100644
--- a/examples/hangman.c
+++ b/examples/hangman.c
@@ -36,14 +36,10 @@
  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/stat.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/rand.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/time.h"
-#include "third_party/zlib/zlib.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <time.h>
 // clang-format off
 
 #define DICT "usr/share/dict/hangman"
diff --git a/examples/hello.c b/examples/hello.c
index f56cbae1e..f3cc59316 100644
--- a/examples/hello.c
+++ b/examples/hello.c
@@ -7,9 +7,8 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/stdio/stdio.h"
+#include <stdio.h>
 
 int main() {
   printf("hello world\n");
-  return 0;
 }
diff --git a/examples/hello2.c b/examples/hello2.c
index ecf749dee..25cbd9a07 100644
--- a/examples/hello2.c
+++ b/examples/hello2.c
@@ -7,7 +7,7 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
+#include <unistd.h>
 
 int main() {
   write(1, "hello world\n", 12);
diff --git a/examples/localtime.c b/examples/localtime.c
deleted file mode 100644
index 70d67c1c2..000000000
--- a/examples/localtime.c
+++ /dev/null
@@ -1,15 +0,0 @@
-#if 0
-/*─────────────────────────────────────────────────────────────────╗
-│ To the extent possible under law, Justine Tunney has waived      │
-│ all copyright and related or neighboring rights to this file,    │
-│ as it is written in the following disclaimers:                   │
-│   • http://unlicense.org/                                        │
-│   • http://creativecommons.org/publicdomain/zero/1.0/            │
-╚─────────────────────────────────────────────────────────────────*/
-#endif
-#include "libc/time.h"
-
-int main(int argc, char *argv[]) {
-  int64_t t = 0;
-  localtime(&t);
-}
diff --git a/examples/loudness.c b/examples/loudness.c
new file mode 100644
index 000000000..194600f08
--- /dev/null
+++ b/examples/loudness.c
@@ -0,0 +1,133 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include <cosmoaudio.h>
+#include <math.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+/**
+ * @fileoverview prints ascii meter of microphone loudness
+ *
+ * 0. -60 dB is nearly silent, barely audible, even in a quiet room
+ * 1. -50 dB is very quiet background sounds
+ * 2. -40 dB is quiet ambient noise
+ * 3. -30 dB is clear but soft sounds
+ * 4. -20 dB is moderate volume, comfortable for extended listening
+ * 5. -10 dB is fairly loud, but not uncomfortable
+ * 6.  -6 dB is loud, but not at full volume
+ * 7.  -3 dB is very loud, approaching system limits
+ * 8.  -1 dB is extremely loud, just below maximum
+ * 9.  -0 dB is maximum volume without distortion
+ */
+
+#define SAMPLING_RATE     44100
+#define ASCII_METER_WIDTH 20
+#define FRAMES_PER_SECOND 30
+#define MIN_DECIBEL       -60
+#define MAX_DECIBEL       0
+#define DEBUG_LOG         1
+
+sig_atomic_t g_done;
+
+void on_signal(int sig) {
+  g_done = 1;
+}
+
+// computes root of mean squares
+double rms(float* p, int n) {
+  double s = 0;
+  for (int i = 0; i < n; ++i)
+    s += p[i] * p[i];
+  return sqrt(s / n);
+}
+
+// converts rms to decibel
+double rms_to_db(double rms) {
+  double db = 20 * log10(rms);
+  db = fmin(db, MAX_DECIBEL);
+  db = fmax(db, MIN_DECIBEL);
+  return db;
+}
+
+int main() {
+  signal(SIGINT, on_signal);
+
+  // how many samples should we process at once
+  int chunkFrames = SAMPLING_RATE / FRAMES_PER_SECOND;
+
+  // configure cosmo audio
+  struct CosmoAudioOpenOptions cao = {0};
+  cao.sizeofThis = sizeof(struct CosmoAudioOpenOptions);
+  cao.deviceType = kCosmoAudioDeviceTypeCapture;
+  cao.sampleRate = SAMPLING_RATE;
+  cao.bufferFrames = chunkFrames * 2;
+  cao.debugLog = DEBUG_LOG;
+  cao.channels = 1;
+
+  // connect to microphone
+  int status;
+  struct CosmoAudio* ca;
+  status = cosmoaudio_open(&ca, &cao);
+  if (status != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "failed to open microphone: %d\n", status);
+    return 1;
+  }
+
+  // allocate memory for audio work area
+  float* chunk = malloc(chunkFrames * sizeof(float));
+  if (!chunk) {
+    fprintf(stderr, "out of memory\n");
+    return 1;
+  }
+
+  while (!g_done) {
+
+    // wait for full chunk of audio to become available
+    int need_in_frames = chunkFrames;
+    status = cosmoaudio_poll(ca, &need_in_frames, NULL);
+    if (status != COSMOAUDIO_SUCCESS) {
+      fprintf(stderr, "failed to poll microphone: %d\n", status);
+      return 2;
+    }
+
+    // read audio frames from microphone ring buffer
+    status = cosmoaudio_read(ca, chunk, chunkFrames);
+    if (status != chunkFrames) {
+      fprintf(stderr, "failed to read microphone: %d\n", status);
+      return 3;
+    }
+
+    // convert audio chunk to to ascii meter
+    char s[ASCII_METER_WIDTH + 1] = {0};
+    double db = rms_to_db(rms(chunk, chunkFrames));
+    double db_range = MAX_DECIBEL - MIN_DECIBEL;
+    int filled_length = (db - MIN_DECIBEL) / db_range * ASCII_METER_WIDTH;
+    for (int i = 0; i < ASCII_METER_WIDTH; ++i) {
+      if (i < filled_length) {
+        s[i] = '=';
+      } else {
+        s[i] = ' ';
+      }
+    }
+    printf("\r%s| %+6.2f dB", s, db);
+    fflush(stdout);
+  }
+  printf("\n");
+
+  // clean up resources
+  status = cosmoaudio_close(ca);
+  if (status != COSMOAUDIO_SUCCESS) {
+    fprintf(stderr, "failed to close microphone: %d\n", status);
+    return 5;
+  }
+  free(chunk);
+}
diff --git a/examples/ls.c b/examples/ls.c
deleted file mode 100644
index 7d8e509f1..000000000
--- a/examples/ls.c
+++ /dev/null
@@ -1,83 +0,0 @@
-#if 0
-/*─────────────────────────────────────────────────────────────────╗
-│ To the extent possible under law, Justine Tunney has waived      │
-│ all copyright and related or neighboring rights to this file,    │
-│ as it is written in the following disclaimers:                   │
-│   • http://unlicense.org/                                        │
-│   • http://creativecommons.org/publicdomain/zero/1.0/            │
-╚─────────────────────────────────────────────────────────────────*/
-#endif
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/dirent.h"
-#include "libc/calls/struct/stat.h"
-#include "libc/log/check.h"
-#include "libc/mem/gc.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/dt.h"
-#include "libc/sysv/consts/s.h"
-#include "libc/x/xasprintf.h"
-
-struct stat st;
-
-const char *TypeToString(uint8_t type) {
-  switch (type) {
-    case DT_UNKNOWN:
-      return "DT_UNKNOWN";
-    case DT_FIFO:
-      return "DT_FIFO";
-    case DT_CHR:
-      return "DT_CHR";
-    case DT_DIR:
-      return "DT_DIR";
-    case DT_BLK:
-      return "DT_BLK";
-    case DT_REG:
-      return "DT_REG";
-    case DT_LNK:
-      return "DT_LNK";
-    case DT_SOCK:
-      return "DT_SOCK";
-    default:
-      return "UNKNOWN";
-  }
-}
-
-void List(const char *path) {
-  DIR *d;
-  struct dirent *e;
-  const char *vpath;
-  if (strcmp(path, ".") == 0) {
-    vpath = "";
-  } else if (!endswith(path, "/")) {
-    vpath = gc(xasprintf("%s/", path));
-  } else {
-    vpath = path;
-  }
-  if (stat(path, &st) != -1) {
-    if (S_ISDIR(st.st_mode)) {
-      CHECK((d = opendir(path)));
-      while ((e = readdir(d))) {
-        printf("0x%016x 0x%016x %-10s %s%s\n", e->d_ino, e->d_off,
-               TypeToString(e->d_type), vpath, e->d_name);
-      }
-      closedir(d);
-    } else {
-      printf("%s\n", path);
-    }
-  } else {
-    fprintf(stderr, "not found: %s\n", path);
-  }
-}
-
-int main(int argc, char *argv[]) {
-  int i;
-  if (argc == 1) {
-    List(".");
-  } else {
-    for (i = 1; i < argc; ++i) {
-      List(argv[i]);
-    }
-  }
-  return 0;
-}
diff --git a/examples/nc.c b/examples/nc.c
index 34483cf01..1e4f9945b 100644
--- a/examples/nc.c
+++ b/examples/nc.c
@@ -7,25 +7,16 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/fmt/conv.h"
-#include "libc/log/log.h"
-#include "libc/macros.h"
-#include "libc/runtime/runtime.h"
-#include "libc/sock/sock.h"
-#include "libc/sock/struct/linger.h"
-#include "libc/sock/struct/pollfd.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/af.h"
-#include "libc/sysv/consts/ipproto.h"
-#include "libc/sysv/consts/poll.h"
-#include "libc/sysv/consts/shut.h"
-#include "libc/sysv/consts/so.h"
-#include "libc/sysv/consts/sock.h"
-#include "libc/sysv/consts/sol.h"
-#include "third_party/getopt/getopt.internal.h"
-#include "third_party/musl/netdb.h"
+#include <cosmo.h>
+#include <getopt.h>
+#include <netdb.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+// clang-format off
 
 /**
  * @fileoverview netcat clone
@@ -36,12 +27,14 @@
  * Here's an example usage:
  *
  *     make -j8 o//examples/nc.com
- *     printf 'GET /\r\nHost: justine.lol\r\n\r\n' | o//examples/nc.com
- * justine.lol 80
+ *     printf 'GET /\r\nHost: justine.lol\r\n\r\n' | o//examples/nc.com justine.lol 80
  *
- * Once upon time we called this command "telnet"
+ * Once upon time we called this command basically "telnet"
  */
 
+#define ARRAYLEN(A) \
+  ((sizeof(A) / sizeof(*(A))) / ((unsigned)!(sizeof(A) % sizeof(*(A)))))
+
 int main(int argc, char *argv[]) {
   ssize_t rc;
   size_t i, got;
diff --git a/examples/parsefloat.c b/examples/parsefloat.c
index c9f049aef..eb8e21aaa 100644
--- a/examples/parsefloat.c
+++ b/examples/parsefloat.c
@@ -1,3 +1,12 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
 #include <stdio.h>
 
 #define PARSE_AND_PRINT(type, scan_fmt, print_fmt, str)      \
diff --git a/examples/pause.c b/examples/pause.c
index be13f5f45..a36ccdec1 100644
--- a/examples/pause.c
+++ b/examples/pause.c
@@ -7,10 +7,10 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/sigaction.h"
-#include "libc/fmt/itoa.h"
-#include "libc/str/str.h"
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 volatile int g_sig;
 
@@ -21,16 +21,13 @@ void OnSig(int sig) {
 int main(int argc, char *argv[]) {
 
   // listen for all signals
-  for (int sig = 1; sig <= NSIG; ++sig) {
+  for (int sig = 1; sig <= NSIG; ++sig)
     signal(sig, OnSig);
-  }
 
   // wait for a signal
-  char ibuf[12];
-  FormatInt32(ibuf, getpid());
-  tinyprint(2, "waiting for signal to be sent to ", ibuf, "\n", NULL);
+  printf("waiting for signal to be sent to my pid %d\n", getpid());
   pause();
 
   // report the signal
-  tinyprint(1, "got ", strsignal(g_sig), "\n", NULL);
+  printf("got %s\n", strsignal(g_sig));
 }
diff --git a/examples/picol.c b/examples/picol.c
index fd54cca53..449e98ed4 100644
--- a/examples/picol.c
+++ b/examples/picol.c
@@ -32,12 +32,9 @@
  * . Formatted as per Cosmopolitan's standards.
  */
 
-#include "libc/fmt/conv.h"
-#include "libc/log/log.h"
-#include "libc/mem/mem.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 enum { PICOL_OK, PICOL_ERR, PICOL_RETURN, PICOL_BREAK, PICOL_CONTINUE };
 enum { PT_ESC, PT_STR, PT_CMD, PT_VAR, PT_SEP, PT_EOL, PT_EOF };
diff --git a/examples/printargs.c b/examples/printargs.c
index 60ce148ed..d65954fcb 100644
--- a/examples/printargs.c
+++ b/examples/printargs.c
@@ -7,7 +7,7 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/runtime/runtime.h"
+#include <cosmo.h>
 
 int main() {
   __printargs("");
diff --git a/examples/romanize.c b/examples/romanize.c
index a31b1ab1f..2b7df6561 100644
--- a/examples/romanize.c
+++ b/examples/romanize.c
@@ -13,11 +13,11 @@
 // TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 // PERFORMANCE OF THIS SOFTWARE.
 
+#include <ctype.h>
 #include <stdio.h>
 #include <string.h>
 #include <wchar.h>
 #include <wctype.h>
-#include "libc/ctype.h"
 
 /**
  * @fileoverview Roman Transliteration, e.g.
diff --git a/examples/script.c b/examples/script.c
index 12ad64a26..8068a75d5 100644
--- a/examples/script.c
+++ b/examples/script.c
@@ -29,29 +29,20 @@
 │ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF       │
 │ SUCH DAMAGE.                                                                 │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/iovec.h"
-#include "libc/calls/struct/stat.h"
-#include "libc/calls/struct/termios.h"
-#include "libc/calls/struct/timeval.h"
-#include "libc/calls/struct/winsize.h"
-#include "libc/calls/termios.h"
-#include "libc/calls/weirdtypes.h"
-#include "libc/errno.h"
-#include "libc/fmt/conv.h"
-#include "libc/intrin/bswap.h"
-#include "libc/log/bsd.h"
-#include "libc/macros.h"
-#include "libc/mem/mem.h"
-#include "libc/paths.h"
-#include "libc/runtime/runtime.h"
-#include "libc/sock/select.h"
-#include "libc/stdio/stdio.h"
-#include "libc/sysv/consts/fileno.h"
-#include "libc/sysv/consts/s.h"
-#include "libc/sysv/consts/termios.h"
-#include "libc/time.h"
-#include "third_party/getopt/getopt.internal.h"
+#include <err.h>
+#include <errno.h>
+#include <paths.h>
+#include <pty.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/uio.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
 // clang-format off
 
 /**
diff --git a/examples/seq.c b/examples/seq.c
index 4d401133b..f8403f60f 100644
--- a/examples/seq.c
+++ b/examples/seq.c
@@ -7,9 +7,8 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/fmt/conv.h"
-#include "libc/fmt/itoa.h"
+#include <cosmo.h>
+#include <stdlib.h>
 
 /**
  * @fileoverview Prints sequence of numbers.
diff --git a/examples/setcontext.c b/examples/setcontext.c
index 07afabe30..ff20aee7e 100644
--- a/examples/setcontext.c
+++ b/examples/setcontext.c
@@ -7,12 +7,9 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/calls/ucontext.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/exit.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
 
 /**
  * @fileoverview swapcontext() and makecontext() example
@@ -33,18 +30,16 @@ static ucontext_t uctx_func2;
 static void func1(void) {
   say("func1: started\n");
   say("func1: swapcontext(&uctx_func1, &uctx_func2)\n");
-  if (swapcontext(&uctx_func1, &uctx_func2) == -1) {
+  if (swapcontext(&uctx_func1, &uctx_func2) == -1)
     handle_error("swapcontext");
-  }
   say("func1: returning\n");
 }
 
 static void func2(void) {
   say("func2: started\n");
   say("func2: swapcontext(&uctx_func2, &uctx_func1)\n");
-  if (swapcontext(&uctx_func2, &uctx_func1) == -1) {
+  if (swapcontext(&uctx_func2, &uctx_func1) == -1)
     handle_error("swapcontext");
-  }
   say("func2: returning\n");
 }
 
@@ -52,17 +47,15 @@ int main(int argc, char *argv[]) {
   char func1_stack[8192];
   char func2_stack[8192];
 
-  if (getcontext(&uctx_func1) == -1) {
+  if (getcontext(&uctx_func1) == -1)
     handle_error("getcontext");
-  }
   uctx_func1.uc_stack.ss_sp = func1_stack;
   uctx_func1.uc_stack.ss_size = sizeof(func1_stack);
   uctx_func1.uc_link = &uctx_main;
   makecontext(&uctx_func1, func1, 0);
 
-  if (getcontext(&uctx_func2) == -1) {
+  if (getcontext(&uctx_func2) == -1)
     handle_error("getcontext");
-  }
   uctx_func2.uc_stack.ss_sp = func2_stack;
   uctx_func2.uc_stack.ss_size = sizeof(func2_stack);
   /* Successor context is f1(), unless argc > 1 */
@@ -70,9 +63,8 @@ int main(int argc, char *argv[]) {
   makecontext(&uctx_func2, func2, 0);
 
   say("main: swapcontext(&uctx_main, &uctx_func2)\n");
-  if (swapcontext(&uctx_main, &uctx_func2) == -1) {
+  if (swapcontext(&uctx_main, &uctx_func2) == -1)
     handle_error("swapcontext");
-  }
 
   say("main: exiting\n");
   exit(EXIT_SUCCESS);
diff --git a/examples/setitimer.c b/examples/setitimer.c
index 89b291941..6d926bca8 100644
--- a/examples/setitimer.c
+++ b/examples/setitimer.c
@@ -7,17 +7,15 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/assert.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/itimerval.h"
-#include "libc/calls/struct/sigaction.h"
-#include "libc/calls/struct/siginfo.h"
-#include "libc/calls/ucontext.h"
-#include "libc/stdio/stdio.h"
-#include "libc/sysv/consts/itimer.h"
-#include "libc/sysv/consts/sa.h"
-#include "libc/sysv/consts/sig.h"
-#include "libc/time.h"
+#include <assert.h>
+#include <signal.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+/**
+ * @fileoverview interval timer tutorial
+ */
 
 volatile bool gotalrm;
 
diff --git a/examples/spawn_bench.c b/examples/spawn_bench.c
index d4ad9114a..66ccdbc6a 100644
--- a/examples/spawn_bench.c
+++ b/examples/spawn_bench.c
@@ -7,24 +7,20 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/atomic.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/timespec.h"
-#include "libc/calls/weirdtypes.h"
-#include "libc/mem/mem.h"
-#include "libc/proc/posix_spawn.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/clock.h"
-#include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/prot.h"
+#include <spawn.h>
+#include <stdalign.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <time.h>
 
 #define ITERATIONS 10
 
-_Alignas(128) int a;
-_Alignas(128) int b;
-_Alignas(128) atomic_int lock;
+alignas(128) int a;
+alignas(128) int b;
+alignas(128) atomic_int lock;
 
 static struct timespec SubtractTime(struct timespec a, struct timespec b) {
   a.tv_sec -= b.tv_sec;
diff --git a/examples/stat.c b/examples/stat.c
index dce122cbb..45e17e354 100644
--- a/examples/stat.c
+++ b/examples/stat.c
@@ -7,19 +7,12 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/struct/stat.h"
-#include "libc/assert.h"
-#include "libc/calls/calls.h"
-#include "libc/errno.h"
-#include "libc/fmt/conv.h"
-#include "libc/log/check.h"
-#include "libc/log/log.h"
-#include "libc/mem/gc.h"
-#include "libc/mem/mem.h"
-#include "libc/stdio/stdio.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/s.h"
-#include "libc/time.h"
+#include <assert.h>
+#include <cosmo.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <time.h>
 
 /**
  * @fileoverview File metadata viewer.
@@ -72,9 +65,15 @@ void PrintFileMetadata(const char *pathname, struct stat *st) {
   printf("\n%s:", pathname);
   if (numeric) {
     fd = atoi(pathname);
-    CHECK_NE(-1, fstat(fd, st), "fd=%d", fd);
+    if (fstat(fd, st)) {
+      perror(pathname);
+      exit(1);
+    }
   } else {
-    CHECK_NE(-1, stat(pathname, st), "pathname=%s", pathname);
+    if (stat(pathname, st)) {
+      perror(pathname);
+      exit(1);
+    }
   }
   printf("\n"
          "%-32s%,ld\n"
diff --git a/examples/statfs.c b/examples/statfs.c
index ce6367794..817017d25 100644
--- a/examples/statfs.c
+++ b/examples/statfs.c
@@ -7,18 +7,19 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/struct/statfs.h"
-#include "libc/dce.h"
-#include "libc/fmt/conv.h"
-#include "libc/log/check.h"
 #include "libc/nt/enum/statfs.h"
-#include "libc/stdio/stdio.h"
-#include "libc/sysv/consts/st.h"
+#include <cosmo.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/vfs.h>
 
-dontinline void ShowIt(const char *path) {
+void ShowIt(const char *path) {
   char ibuf[21];
   struct statfs sf = {0};
-  CHECK_NE(-1, statfs(path, &sf));
+  if (statfs(path, &sf)) {
+    perror(path);
+    exit(1);
+  }
 
   printf("filesystem %s\n", path);
   printf("f_type    = %#x (%s)\n", sf.f_type, sf.f_fstypename);
diff --git a/examples/stringbuffer.c b/examples/stringbuffer.c
deleted file mode 100644
index 4f965be2f..000000000
--- a/examples/stringbuffer.c
+++ /dev/null
@@ -1,36 +0,0 @@
-#if 0
-/*─────────────────────────────────────────────────────────────────╗
-│ To the extent possible under law, Justine Tunney has waived      │
-│ all copyright and related or neighboring rights to this file,    │
-│ as it is written in the following disclaimers:                   │
-│   • http://unlicense.org/                                        │
-│   • http://creativecommons.org/publicdomain/zero/1.0/            │
-╚─────────────────────────────────────────────────────────────────*/
-#endif
-#include "libc/calls/calls.h"
-#include "libc/log/check.h"
-#include "libc/mem/mem.h"
-#include "libc/stdio/append.h"
-#include "libc/str/str.h"
-
-/**
- * @fileoverview Fast Growable Strings Tutorial
- */
-
-int main(int argc, char *argv[]) {
-  char *b = 0;
-  appendf(&b, "hello ");  // guarantees nul terminator
-  CHECK_EQ(6, strlen(b));
-  CHECK_EQ(6, appendz(b).i);
-  appendf(&b, " world\n");
-  CHECK_EQ(13, strlen(b));
-  CHECK_EQ(13, appendz(b).i);
-  appendd(&b, "\0", 1);  // supports binary
-  CHECK_EQ(13, strlen(b));
-  CHECK_EQ(14, appendz(b).i);
-  appendf(&b, "%d arg%s\n", argc, argc == 1 ? "" : "s");
-  appendf(&b, "%s\n", "have a nice day");
-  write(1, b, appendz(b).i);
-  free(b);
-  return 0;
-}
diff --git a/examples/sysconf.c b/examples/sysconf.c
index 19a91e6b6..553b3a245 100644
--- a/examples/sysconf.c
+++ b/examples/sysconf.c
@@ -7,8 +7,8 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/runtime/sysconf.h"
-#include "libc/stdio/stdio.h"
+#include <stdio.h>
+#include <unistd.h>
 
 #define SYSCONF(NAME) printf("%-24s %,ld\n", #NAME, sysconf(NAME))
 
diff --git a/examples/sysinfo.c b/examples/sysinfo.c
index 4892a8183..afd2c5bca 100644
--- a/examples/sysinfo.c
+++ b/examples/sysinfo.c
@@ -7,19 +7,19 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/struct/sysinfo.h"
-#include "libc/calls/struct/timespec.h"
-#include "libc/fmt/conv.h"
-#include "libc/fmt/itoa.h"
-#include "libc/log/check.h"
-#include "libc/stdio/stdio.h"
-#include "libc/sysv/consts/clock.h"
+#include <cosmo.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/sysinfo.h>
 
 int main(int argc, char *argv[]) {
   int64_t x;
   char ibuf[21];
   struct sysinfo si;
-  CHECK_NE(-1, sysinfo(&si));
+  if (sysinfo(&si)) {
+    perror("sysinfo");
+    exit(1);
+  }
 
   printf("%-16s", "uptime");
   x = si.uptime / (24 * 60 * 60);
diff --git a/examples/system.c b/examples/system.c
index 070665191..dcb2be248 100644
--- a/examples/system.c
+++ b/examples/system.c
@@ -7,9 +7,7 @@
 │   • http://creativecommons.org/publicdomain/zero/1.0/            │
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
-#include "libc/calls/calls.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/stdio.h"
+#include <stdlib.h>
 
 /**
  * @fileoverview Cosmopolitan Command Interpreter Demo
diff --git a/libc/isystem/sys/vfs.h b/libc/isystem/sys/vfs.h
index 9d8ac9412..2904d0feb 100644
--- a/libc/isystem/sys/vfs.h
+++ b/libc/isystem/sys/vfs.h
@@ -1,4 +1,5 @@
 #ifndef COSMOPOLITAN_LIBC_ISYSTEM_SYS_VFS_H_
 #define COSMOPOLITAN_LIBC_ISYSTEM_SYS_VFS_H_
 #include "libc/calls/struct/statfs.h"
+#include "libc/sysv/consts/st.h"
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_SYS_VFS_H_ */