Threads cleanup

20 files changed, 222 insertions, 445 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b5d1cc2..be0471c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -98,12 +98,12 @@ if(NOT KIT_HAVE_MALLOC)
   set(KIT_DISABLE_SYSTEM_MALLOC ON)
 endif()
 
-if(KIT_HAVE_STRUCT_TIMESPEC)
-  target_compile_definitions(${KIT_LIBRARY} PUBLIC KIT_HAVE_STRUCT_TIMESPEC)
+if(NOT KIT_HAVE_STRUCT_TIMESPEC)
+  target_compile_definitions(${KIT_LIBRARY} PUBLIC KIT_NEED_STRUCT_TIMESPEC)
 endif()
 
-if(KIT_HAVE_TIMESPEC_GET)
-  target_compile_definitions(${KIT_LIBRARY} PUBLIC KIT_HAVE_TIMESPEC_GET)
+if(NOT KIT_HAVE_TIMESPEC_GET)
+  target_compile_definitions(${KIT_LIBRARY} PUBLIC KIT_NEED_TIMESPEC_GET)
 endif()
 
 if(KIT_DISABLE_SYSTEM_MALLOC)
diff --git a/source/kit/CMakeLists.txt b/source/kit/CMakeLists.txt
index f9a30d2..e12077a 100644
--- a/source/kit/CMakeLists.txt
+++ b/source/kit/CMakeLists.txt
@@ -1,8 +1,8 @@
 target_sources(
   ${KIT_LIBRARY}
     PRIVATE
-      input_buffer.c bigint.c status.c threads.win32.c time.c
-      secure_random.c atomic.win32.c threads.posix.c condition_variable.c
+      input_buffer.c bigint.c status.c time.c secure_random.c
+      thread.posix.c atomic.win32.c condition_variable.c thread.win32.c
       move_back.c input_stream.c lower_bound.c file.c string_ref.c
       async_function.c allocator.c array_ref.c dynamic_array.c mutex.c
       mersenne_twister_64.c
@@ -13,7 +13,7 @@ target_sources(
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/atomic.h>
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/allocator.h>
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/string_ref.h>
-      $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/threads.h>
+      $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/thread.h>
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/bigint.h>
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/dynamic_array.h>
       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/condition_variable.h>
diff --git a/source/kit/condition_variable.h b/source/kit/condition_variable.h
index dd3b891..0e4630d 100644
--- a/source/kit/condition_variable.h
+++ b/source/kit/condition_variable.h
@@ -1,6 +1,39 @@
 #ifndef KIT_CONDITION_VARIABLE_H
 #define KIT_CONDITION_VARIABLE_H
 
-#include "threads.h"
+#ifndef KIT_DISABLE_SYSTEM_THREADS
+#  include "mutex.h"
+
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+
+#  if defined(_WIN32) && !defined(__CYGWIN__)
+typedef struct {
+  void *Ptr;
+} cnd_t;
+
+typedef struct {
+  volatile uintptr_t status;
+} once_flag;
+#  else
+typedef pthread_cond_t cnd_t;
+typedef pthread_once_t once_flag;
+#  endif
+
+void call_once(once_flag *, void (*)(void));
+int  cnd_broadcast(cnd_t *);
+void cnd_destroy(cnd_t *);
+int  cnd_init(cnd_t *);
+int  cnd_signal(cnd_t *);
+int  cnd_timedwait(cnd_t *__restrict, mtx_t *__restrict mtx_,
+                   const struct timespec *__restrict);
+int  cnd_wait(cnd_t *, mtx_t *mtx_);
+
+#  ifdef __cplusplus
+}
+#  endif
+
+#endif
 
 #endif
diff --git a/source/kit/mersenne_twister_64.c b/source/kit/mersenne_twister_64.c
index 28f8b3b..0570a1f 100644
--- a/source/kit/mersenne_twister_64.c
+++ b/source/kit/mersenne_twister_64.c
@@ -1,7 +1,5 @@
 #include "mersenne_twister_64.h"
 
-#include "secure_random.h"
-
 #define MM 156
 #define MATRIX_A 0xb5026f5aa96619e9ull
 #define UM 0xffffffff80000000ull
@@ -60,9 +58,3 @@ uint64_t kit_mt64_generate(kit_mt64_state_t *const state) {
 
   return x;
 }
-
-uint64_t kit_mt64_seed() {
-  uint64_t seed;
-  kit_secure_random(sizeof seed, &seed);
-  return seed;
-}
diff --git a/source/kit/mersenne_twister_64.h b/source/kit/mersenne_twister_64.h
index fb509c2..67a4d22 100644
--- a/source/kit/mersenne_twister_64.h
+++ b/source/kit/mersenne_twister_64.h
@@ -24,8 +24,6 @@ void kit_mt64_init(kit_mt64_state_t *state, uint64_t seed);
 
 uint64_t kit_mt64_generate(kit_mt64_state_t *state);
 
-uint64_t kit_mt64_seed();
-
 #ifndef KIT_DISABLE_SHORT_NAMES
 #  define mt64_state_t kit_mt64_state_t
 #  define mt64_init_array kit_mt64_init_array
diff --git a/source/kit/mutex.h b/source/kit/mutex.h
index 0b7c548..e5d2e40 100644
--- a/source/kit/mutex.h
+++ b/source/kit/mutex.h
@@ -1,6 +1,48 @@
 #ifndef KIT_MUTEX_H
 #define KIT_MUTEX_H
 
-#include "threads.h"
+#ifndef KIT_DISABLE_SYSTEM_THREADS
+#  include "time.h"
+
+#  if !defined(_WIN32) || defined(__CYGWIN__)
+#    include <pthread.h>
+#  endif
+
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+
+#  if defined(_WIN32) && !defined(__CYGWIN__)
+typedef struct {
+  void     *DebugInfo;
+  long      LockCount;
+  long      RecursionCount;
+  void     *OwningThread;
+  void     *LockSemaphore;
+  uintptr_t SpinCount;
+} mtx_t;
+#  else
+typedef pthread_mutex_t mtx_t;
+#  endif
+
+enum {
+  mtx_plain     = 0,
+  mtx_recursive = 1,
+  mtx_timed     = 2,
+};
+
+void mtx_destroy(mtx_t *mtx_);
+int  mtx_init(mtx_t *mtx_, int);
+int  mtx_lock(mtx_t *mtx_);
+int  mtx_timedlock(mtx_t *__restrict mtx_,
+                   const struct timespec *__restrict);
+int  mtx_trylock(mtx_t *mtx_);
+int  mtx_unlock(mtx_t *mtx_);
+
+#  ifdef __cplusplus
+}
+#  endif
+
+#endif
 
 #endif
diff --git a/source/kit/secure_random.c b/source/kit/secure_random.c
index 8f48c9d..013fd52 100644
--- a/source/kit/secure_random.c
+++ b/source/kit/secure_random.c
@@ -1,8 +1,10 @@
 #include "secure_random.h"
 
+#include "condition_variable.h"
 #include "mersenne_twister_64.h"
 #include "mutex.h"
 #include "time.h"
+#include <assert.h>
 #include <stdio.h>
 
 #if defined(_WIN32) && !defined(__CYGWIN__)
@@ -28,12 +30,19 @@ static uint64_t get_available_memory() {
 }
 
 #ifndef KIT_DISABLE_SYSTEM_THREADS
-static mtx_t kit_secure_random_fallback_mutex;
+static once_flag kit_secure_random_fallback_flag;
+static mtx_t     kit_secure_random_fallback_mutex;
+
+static void secure_random_fallback_init() {
+  mtx_init(&kit_secure_random_fallback_mutex, mtx_plain);
+}
 #endif
 
 static void secure_random_fallback(ptrdiff_t const size,
                                    void *const     data) {
 #ifndef KIT_DISABLE_SYSTEM_THREADS
+  call_once(&kit_secure_random_fallback_flag,
+            secure_random_fallback_init);
   mtx_lock(&kit_secure_random_fallback_mutex);
 #endif
 
@@ -82,18 +91,6 @@ static void secure_random_fallback(ptrdiff_t const size,
 #endif
 }
 
-void kit_secure_random_init() {
-#ifndef KIT_DISABLE_SYSTEM_THREADS
-  mtx_init(&kit_secure_random_fallback_mutex, mtx_plain);
-#endif
-}
-
-void kit_secure_random_cleanup() {
-#ifndef KIT_DISABLE_SYSTEM_THREADS
-  mtx_destroy(&kit_secure_random_fallback_mutex);
-#endif
-}
-
 void kit_secure_random(ptrdiff_t const size, void *const data) {
   if (size <= 0)
     return;
diff --git a/source/kit/secure_random.h b/source/kit/secure_random.h
index 5b461f9..758478d 100644
--- a/source/kit/secure_random.h
+++ b/source/kit/secure_random.h
@@ -9,14 +9,9 @@
 extern "C" {
 #endif
 
-void kit_secure_random_init();
-void kit_secure_random_cleanup();
-
 void kit_secure_random(ptrdiff_t size, void *data);
 
 #ifndef KIT_DISABLE_SHORT_NAMES
-#  define secure_random_init kit_secure_random_init
-#  define secure_random_cleanup kit_secure_random_cleanup
 #  define secure_random kit_secure_random
 #endif
 
diff --git a/source/kit/thread.h b/source/kit/thread.h
new file mode 100644
index 0000000..f64264e
--- /dev/null
+++ b/source/kit/thread.h
@@ -0,0 +1,92 @@
+#ifndef KIT_THREAD_H
+#define KIT_THREAD_H
+
+#ifndef KIT_DISABLE_SYSTEM_THREADS
+#  include "time.h"
+#  include <stddef.h>
+
+#  if defined(__cplusplus)
+#    define _Noreturn [[noreturn]]
+#  elif defined(_MSC_VER)
+#    define _Noreturn __declspec(noreturn)
+#  endif
+
+#  if !defined(_WIN32) || defined(__CYGWIN__)
+#    include <pthread.h>
+#  endif
+
+#  ifndef _Thread_local
+#    if defined(__cplusplus)
+/* C++11 doesn't need `_Thread_local` keyword or macro */
+#    elif !defined(__STDC_NO_THREADS__)
+/* threads are optional in C11, _Thread_local present in this
+ * condition */
+#    elif defined(_MSC_VER)
+#      define _Thread_local __declspec(thread)
+#    elif defined(__GNUC__)
+#      define _Thread_local __thread
+#    else
+/* Leave _Thread_local undefined so that use of _Thread_local would
+ * not promote to a non-thread-local global variable
+ */
+#    endif
+#  endif
+
+#  if !defined(__cplusplus)
+/*
+ * C11 thread_local() macro
+ * C++11 and above already have thread_local keyword
+ */
+#    ifndef thread_local
+#      if _MSC_VER
+#        define thread_local __declspec(thread)
+#      else
+#        define thread_local _Thread_local
+#      endif
+#    endif
+#  endif
+
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+
+typedef void (*tss_dtor_t)(void *);
+typedef int (*thrd_start_t)(void *);
+
+#  if defined(_WIN32) && !defined(__CYGWIN__)
+typedef struct {
+  void *handle;
+} thrd_t;
+typedef unsigned long tss_t;
+#  else
+typedef pthread_t     thrd_t;
+typedef pthread_key_t tss_t;
+#  endif
+
+enum {
+  thrd_success = 0,
+  thrd_timedout,
+  thrd_error,
+  thrd_busy,
+  thrd_nomem,
+  thrd_wrong_stack_size
+};
+
+int            thrd_create(thrd_t *, thrd_start_t, void *);
+int            thrd_create_with_stack(thrd_t *, thrd_start_t, void *,
+                                      ptrdiff_t stack_size);
+thrd_t         thrd_current(void);
+int            thrd_detach(thrd_t);
+int            thrd_equal(thrd_t, thrd_t);
+_Noreturn void thrd_exit(int);
+int            thrd_join(thrd_t, int *);
+int            thrd_sleep(const struct timespec *, struct timespec *);
+void           thrd_yield(void);
+
+#  ifdef __cplusplus
+}
+#  endif
+
+#endif
+
+#endif
diff --git a/source/kit/threads.posix.c b/source/kit/thread.posix.c
index efedbaa..442d7f8 100644
--- a/source/kit/threads.posix.c
+++ b/source/kit/thread.posix.c
@@ -1,34 +1,3 @@
-/*
- * C11 <threads.h> emulation library
- *
- * (C) Copyright yohhoy 2012.
- * Distributed under the Boost Software License, Version 1.0.
- *
- * Permission is hereby granted, free of charge, to any person or
- * organization obtaining a copy of the software and accompanying
- * documentation covered by this license (the "Software") to use,
- * reproduce, display, distribute, execute, and transmit the Software,
- * and to prepare [[derivative work]]s of the Software, and to permit
- * third-parties to whom the Software is furnished to do so, all
- * subject to the following:
- *
- * The copyright notices in the Software and this entire statement,
- * including the above license grant, this restriction and the
- * following disclaimer, must be included in all copies of the
- * Software, in whole or in part, and all derivative works of the
- * Software, unless such copies or derivative works are solely in the
- * form of machine-executable object code generated by a source
- * language processor.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
- * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE
- * DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER
- * LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
 #ifndef KIT_DISABLE_SYSTEM_THREADS
 #  if !defined(_WIN32) || defined(__CYGWIN__)
 
@@ -36,12 +5,14 @@
 #    include <errno.h>
 #    include <limits.h>
 #    include <sched.h>
-#    include <stdint.h> /* for intptr_t */
+#    include <stdint.h> /* intptr_t */
 #    include <stdlib.h>
 #    include <unistd.h>
 
 #    include "allocator.h"
-#    include "threads.h"
+#    include "condition_variable.h"
+#    include "mutex.h"
+#    include "thread.h"
 
 /*
 Configuration macro:
@@ -55,8 +26,6 @@ Configuration macro:
 #      define EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
 #    endif
 
-/*---------------------------- types ----------------------------*/
-
 /*
 Implementation limits:
   - Conditionally emulation for "mutex with timeout"
@@ -74,40 +43,32 @@ static void *impl_thrd_routine(void *p) {
   return (void *) (intptr_t) pack.func(pack.arg);
 }
 
-/*--------------- 7.25.2 Initialization functions ---------------*/
-// 7.25.2.1
 void call_once(once_flag *flag, void (*func)(void)) {
   pthread_once(flag, func);
 }
 
-/*------------- 7.25.3 Condition variable functions -------------*/
-// 7.25.3.1
 int cnd_broadcast(cnd_t *cond) {
   assert(cond != NULL);
   return (pthread_cond_broadcast(cond) == 0) ? thrd_success
                                              : thrd_error;
 }
 
-// 7.25.3.2
 void cnd_destroy(cnd_t *cond) {
   assert(cond);
   pthread_cond_destroy(cond);
 }
 
-// 7.25.3.3
 int cnd_init(cnd_t *cond) {
   assert(cond != NULL);
   return (pthread_cond_init(cond, NULL) == 0) ? thrd_success
                                               : thrd_error;
 }
 
-// 7.25.3.4
 int cnd_signal(cnd_t *cond) {
   assert(cond != NULL);
   return (pthread_cond_signal(cond) == 0) ? thrd_success : thrd_error;
 }
 
-// 7.25.3.5
 int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
                   const struct timespec *abs_time) {
   int rt;
@@ -122,7 +83,6 @@ int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
   return (rt == 0) ? thrd_success : thrd_error;
 }
 
-// 7.25.3.6
 int cnd_wait(cnd_t *cond, mtx_t *mtx) {
   assert(mtx != NULL);
   assert(cond != NULL);
@@ -130,8 +90,6 @@ int cnd_wait(cnd_t *cond, mtx_t *mtx) {
                                              : thrd_error;
 }
 
-/*-------------------- 7.25.4 Mutex functions --------------------*/
-// 7.25.4.1
 void mtx_destroy(mtx_t *mtx) {
   assert(mtx != NULL);
   pthread_mutex_destroy(mtx);
@@ -163,7 +121,6 @@ __attribute__((weak)) int pthread_mutexattr_destroy(
     pthread_mutexattr_t *attr);
 #    endif
 
-// 7.25.4.2
 int mtx_init(mtx_t *mtx, int type) {
   pthread_mutexattr_t attr;
   assert(mtx != NULL);
@@ -184,13 +141,11 @@ int mtx_init(mtx_t *mtx, int type) {
   return thrd_success;
 }
 
-// 7.25.4.3
 int mtx_lock(mtx_t *mtx) {
   assert(mtx != NULL);
   return (pthread_mutex_lock(mtx) == 0) ? thrd_success : thrd_error;
 }
 
-// 7.25.4.4
 int mtx_timedlock(mtx_t *mtx, const struct timespec *ts) {
   assert(mtx != NULL);
   assert(ts != NULL);
@@ -217,20 +172,16 @@ int mtx_timedlock(mtx_t *mtx, const struct timespec *ts) {
   }
 }
 
-// 7.25.4.5
 int mtx_trylock(mtx_t *mtx) {
   assert(mtx != NULL);
   return (pthread_mutex_trylock(mtx) == 0) ? thrd_success : thrd_busy;
 }
 
-// 7.25.4.6
 int mtx_unlock(mtx_t *mtx) {
   assert(mtx != NULL);
   return (pthread_mutex_unlock(mtx) == 0) ? thrd_success : thrd_error;
 }
 
-/*------------------- 7.25.5 Thread functions -------------------*/
-// 7.25.5.1
 int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
                            ptrdiff_t const require_stack_size) {
   impl_thrd_param_t *pack;
@@ -253,7 +204,7 @@ int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
   }
   kit_allocator_t alloc = kit_alloc_default();
   pack                  = (impl_thrd_param_t *) alloc.allocate(
-      alloc.state, sizeof(impl_thrd_param_t));
+                       alloc.state, sizeof(impl_thrd_param_t));
   if (!pack) {
     if (attr_p)
       pthread_attr_destroy(attr_p);
@@ -276,27 +227,22 @@ int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
 int thrd_create(thrd_t *thr, thrd_start_t func, void *arg) {
   return thrd_create_with_stack(thr, func, arg, 0);
 }
-// 7.25.5.2
 thrd_t thrd_current(void) {
   return pthread_self();
 }
 
-// 7.25.5.3
 int thrd_detach(thrd_t thr) {
   return (pthread_detach(thr) == 0) ? thrd_success : thrd_error;
 }
 
-// 7.25.5.4
 int thrd_equal(thrd_t thr0, thrd_t thr1) {
   return pthread_equal(thr0, thr1);
 }
 
-// 7.25.5.5
 _Noreturn void thrd_exit(int res) {
   pthread_exit((void *) (intptr_t) res);
 }
 
-// 7.25.5.6
 int thrd_join(thrd_t thr, int *res) {
   void *code;
   if (pthread_join(thr, &code) != 0)
@@ -306,14 +252,12 @@ int thrd_join(thrd_t thr, int *res) {
   return thrd_success;
 }
 
-// 7.25.5.7
 int thrd_sleep(const struct timespec *time_point,
                struct timespec       *remaining) {
   assert(time_point != NULL);
   return nanosleep(time_point, remaining);
 }
 
-// 7.25.5.8
 void thrd_yield(void) {
   sched_yield();
 }
diff --git a/source/kit/threads.win32.c b/source/kit/thread.win32.c
index 534b01c..7e1dda8 100644
--- a/source/kit/threads.win32.c
+++ b/source/kit/thread.win32.c
@@ -1,45 +1,16 @@
-/*
- * C11 <threads.h> emulation library
- *
- * (C) Copyright yohhoy 2012.
- * Distributed under the Boost Software License, Version 1.0.
- *
- * Permission is hereby granted, free of charge, to any person or
- * organization obtaining a copy of the software and accompanying
- * documentation covered by this license (the "Software") to use,
- * reproduce, display, distribute, execute, and transmit the Software,
- * and to prepare [[derivative work]]s of the Software, and to permit
- * third-parties to whom the Software is furnished to do so, all
- * subject to the following:
- *
- * The copyright notices in the Software and this entire statement,
- * including the above license grant, this restriction and the
- * following disclaimer, must be included in all copies of the
- * Software, in whole or in part, and all derivative works of the
- * Software, unless such copies or derivative works are solely in the
- * form of machine-executable object code generated by a source
- * language processor.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
- * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE
- * DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER
- * LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
 #ifndef KIT_DISABLE_SYSTEM_THREADS
 #  if defined(_WIN32) && !defined(__CYGWIN__)
 
 #    include <assert.h>
 #    include <errno.h>
 #    include <limits.h>
-#    include <process.h> // MSVCRT
+#    include <process.h>
 #    include <stdbool.h>
 #    include <stdlib.h>
 
 #    include "allocator.h"
+#    include "condition_variable.h"
+#    include "mutex.h"
 #    include "threads.h"
 
 #    ifndef WIN32_LEAN_AND_MEAN
@@ -60,15 +31,15 @@ Configuration macro:
 */
 
 #    if _WIN32_WINNT >= 0x0600
-// Prefer native WindowsAPI on newer environment.
+/* Prefer native WindowsAPI on newer environment. */
 #      if !defined(__MINGW32__)
 #        define EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 #      endif
 #    endif
 #    define EMULATED_THREADS_TSS_DTOR_SLOTNUM \
-      64 // see TLS_MINIMUM_AVAILABLE
+      64 /* see TLS_MINIMUM_AVAILABLE */
 
-// check configuration
+/* check configuration */
 #    if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && \
         (_WIN32_WINNT < 0x0600)
 #      error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
@@ -136,6 +107,7 @@ static DWORD impl_abs2relmsec(const struct timespec *abs_time) {
 struct impl_call_once_param {
   void (*func)(void);
 };
+
 static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce,
                                              PVOID      Parameter,
                                              PVOID     *Context) {
@@ -143,10 +115,10 @@ static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce,
       Parameter;
   (param->func)();
   ((void) InitOnce);
-  ((void) Context); // suppress warning
+  ((void) Context); /* suppress warning */
   return TRUE;
 }
-#    endif // ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
+#    endif /* ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE */
 
 static struct impl_tss_dtor_entry {
   tss_t      key;
@@ -177,8 +149,6 @@ static void impl_tss_dtor_invoke(void) {
   }
 }
 
-/*--------------- 7.25.2 Initialization functions ---------------*/
-// 7.25.2.1
 void call_once(once_flag *flag, void (*func)(void)) {
   assert(flag && func);
 #    ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
@@ -204,36 +174,30 @@ void call_once(once_flag *flag, void (*func)(void)) {
 #    endif
 }
 
-/*------------- 7.25.3 Condition variable functions -------------*/
-// 7.25.3.1
 int cnd_broadcast(cnd_t *cond) {
   assert(cond != NULL);
   WakeAllConditionVariable((PCONDITION_VARIABLE) cond);
   return thrd_success;
 }
 
-// 7.25.3.2
 void cnd_destroy(cnd_t *cond) {
-  (void) cond;
   assert(cond != NULL);
-  // do nothing
+  /* do nothing */
+  (void) cond;
 }
 
-// 7.25.3.3
 int cnd_init(cnd_t *cond) {
   assert(cond != NULL);
   InitializeConditionVariable((PCONDITION_VARIABLE) cond);
   return thrd_success;
 }
 
-// 7.25.3.4
 int cnd_signal(cnd_t *cond) {
   assert(cond != NULL);
   WakeConditionVariable((PCONDITION_VARIABLE) cond);
   return thrd_success;
 }
 
-// 7.25.3.5
 int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
                   const struct timespec *abs_time) {
   assert(cond != NULL);
@@ -247,7 +211,6 @@ int cnd_timedwait(cnd_t *cond, mtx_t *mtx,
                                            : thrd_error;
 }
 
-// 7.25.3.6
 int cnd_wait(cnd_t *cond, mtx_t *mtx) {
   assert(cond != NULL);
   assert(mtx != NULL);
@@ -256,14 +219,11 @@ int cnd_wait(cnd_t *cond, mtx_t *mtx) {
   return thrd_success;
 }
 
-/*-------------------- 7.25.4 Mutex functions --------------------*/
-// 7.25.4.1
 void mtx_destroy(mtx_t *mtx) {
   assert(mtx);
   DeleteCriticalSection((PCRITICAL_SECTION) mtx);
 }
 
-// 7.25.4.2
 int mtx_init(mtx_t *mtx, int type) {
   assert(mtx != NULL);
   if (type != mtx_plain && type != mtx_timed &&
@@ -274,27 +234,24 @@ int mtx_init(mtx_t *mtx, int type) {
   return thrd_success;
 }
 
-// 7.25.4.3
 int mtx_lock(mtx_t *mtx) {
   assert(mtx != NULL);
   EnterCriticalSection((PCRITICAL_SECTION) mtx);
   return thrd_success;
 }
 
-// 7.25.4.4
 int mtx_timedlock(mtx_t *mtx, const struct timespec *ts) {
   assert(mtx != NULL);
   assert(ts != NULL);
   while (mtx_trylock(mtx) != thrd_success) {
     if (impl_abs2relmsec(ts) == 0)
       return thrd_timedout;
-    // busy loop!
+    /* busy loop! */
     thrd_yield();
   }
   return thrd_success;
 }
 
-// 7.25.4.5
 int mtx_trylock(mtx_t *mtx) {
   assert(mtx != NULL);
   return TryEnterCriticalSection((PCRITICAL_SECTION) mtx)
@@ -302,15 +259,12 @@ int mtx_trylock(mtx_t *mtx) {
              : thrd_busy;
 }
 
-// 7.25.4.6
 int mtx_unlock(mtx_t *mtx) {
   assert(mtx != NULL);
   LeaveCriticalSection((PCRITICAL_SECTION) mtx);
   return thrd_success;
 }
 
-/*------------------- 7.25.5 Thread functions -------------------*/
-// 7.25.5.1
 int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
                            ptrdiff_t const stack_size) {
   impl_thrd_param_t *pack;
@@ -319,7 +273,7 @@ int thrd_create_with_stack(thrd_t *thr, thrd_start_t func, void *arg,
   assert(stack_size >= 0 && stack_size < 0x100000000);
   kit_allocator_t alloc = kit_alloc_default();
   pack                  = (impl_thrd_param_t *) alloc.allocate(
-      alloc.state, (sizeof(impl_thrd_param_t)));
+                       alloc.state, (sizeof(impl_thrd_param_t)));
   if (!pack)
     return thrd_nomem;
   pack->func  = func;
@@ -344,7 +298,6 @@ int thrd_create(thrd_t *thr, thrd_start_t func, void *arg) {
   return thrd_create_with_stack(thr, func, arg, 0);
 }
 
-// 7.25.5.2
 thrd_t thrd_current(void) {
   /* GetCurrentThread() returns a pseudo-handle, which we need
    * to pass to DuplicateHandle(). Only the resulting handle can be
@@ -378,23 +331,19 @@ thrd_t thrd_current(void) {
   return state->thrd;
 }
 
-// 7.25.5.3
 int thrd_detach(thrd_t thr) {
   CloseHandle(thr.handle);
   return thrd_success;
 }
 
-// 7.25.5.4
 int thrd_equal(thrd_t thr0, thrd_t thr1) {
   return GetThreadId(thr0.handle) == GetThreadId(thr1.handle);
 }
 
-// 7.25.5.5
 _Noreturn void thrd_exit(int res) {
   _endthreadex((unsigned) res);
 }
 
-// 7.25.5.6
 int thrd_join(thrd_t thr, int *res) {
   DWORD w, code;
   if (thr.handle == NULL) {
@@ -414,7 +363,6 @@ int thrd_join(thrd_t thr, int *res) {
   return thrd_success;
 }
 
-// 7.25.5.7
 int thrd_sleep(const struct timespec *time_point,
                struct timespec       *remaining) {
   (void) remaining;
@@ -424,10 +372,9 @@ int thrd_sleep(const struct timespec *time_point,
   return 0;
 }
 
-// 7.25.5.8
 void thrd_yield(void) {
   SwitchToThread();
 }
 
 #  endif
-#endif /* KIT_DISABLE_SYSTEM_THREADS */
+#endif
diff --git a/source/kit/threads.h b/source/kit/threads.h
deleted file mode 100644
index 5cfb5d3..0000000
--- a/source/kit/threads.h
+++ /dev/null
@@ -1,197 +0,0 @@
-/*
- * C11 <threads.h> emulation library
- *
- * (C) Copyright yohhoy 2012.
- * Copyright 2022 Yonggang Luo
- * Distributed under the Boost Software License, Version 1.0.
- *
- * Permission is hereby granted, free of charge, to any person or
- * organization obtaining a copy of the software and accompanying
- * documentation covered by this license (the "Software") to use,
- * reproduce, display, distribute, execute, and transmit the Software,
- * and to prepare [[derivative work]]s of the Software, and to permit
- * third-parties to whom the Software is furnished to do so, all
- * subject to the following:
- *
- * The copyright notices in the Software and this entire statement,
- * including the above license grant, this restriction and the
- * following disclaimer, must be included in all copies of the
- * Software, in whole or in part, and all derivative works of the
- * Software, unless such copies or derivative works are solely in the
- * form of machine-executable object code generated by a source
- * language processor.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
- * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE
- * DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER
- * LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
-
-#ifndef KIT_THREADS_H
-#define KIT_THREADS_H
-
-#ifndef KIT_DISABLE_SYSTEM_THREADS
-#  include "time.h"
-
-#  include <errno.h>
-#  include <limits.h>
-#  include <stddef.h>
-#  include <stdlib.h>
-
-#  ifdef _MSC_VER
-#    define _Noreturn __declspec(noreturn)
-#  endif
-
-#  if defined(_WIN32) && !defined(__CYGWIN__)
-#    include <io.h>      /* close */
-#    include <process.h> /* _exit */
-#  else
-#    include <pthread.h>
-#    include <unistd.h> /* close, _exit */
-#  endif
-
-/*---------------------------- macros ---------------------------*/
-
-#  ifndef _Thread_local
-#    if defined(__cplusplus)
-/* C++11 doesn't need `_Thread_local` keyword or macro */
-#    elif !defined(__STDC_NO_THREADS__)
-/* threads are optional in C11, _Thread_local present in this
- * condition */
-#    elif defined(_MSC_VER)
-#      define _Thread_local __declspec(thread)
-#    elif defined(__GNUC__)
-#      define _Thread_local __thread
-#    else
-/* Leave _Thread_local undefined so that use of _Thread_local would
- * not promote to a non-thread-local global variable
- */
-#    endif
-#  endif
-
-#  if !defined(__cplusplus)
-/*
- * C11 thread_local() macro
- * C++11 and above already have thread_local keyword
- */
-#    ifndef thread_local
-#      if _MSC_VER
-#        define thread_local __declspec(thread)
-#      else
-#        define thread_local _Thread_local
-#      endif
-#    endif
-#  endif
-
-#  ifdef __cplusplus
-extern "C" {
-#  endif
-
-/*---------------------------- types ----------------------------*/
-typedef void (*tss_dtor_t)(void *);
-typedef int (*thrd_start_t)(void *);
-
-#  if defined(_WIN32) && !defined(__CYGWIN__)
-typedef struct {
-  void *Ptr;
-} cnd_t;
-/* Define thrd_t as struct type intentionally for avoid use of thrd_t
- * as pointer type */
-typedef struct {
-  void *handle;
-} thrd_t;
-typedef unsigned long tss_t;
-typedef struct {
-  void     *DebugInfo;
-  long      LockCount;
-  long      RecursionCount;
-  void     *OwningThread;
-  void     *LockSemaphore;
-  uintptr_t SpinCount;
-} mtx_t; /* Mock of CRITICAL_SECTION */
-typedef struct {
-  volatile uintptr_t status;
-} once_flag;
-// FIXME: temporary non-standard hack to ease transition
-#    define KIT_MTX_INITIALIZER_NP_ \
-      { (void *) -1, -1, 0, 0, 0, 0 }
-#    define ONCE_FLAG_INIT \
-      { 0 }
-#    define TSS_DTOR_ITERATIONS 1
-#  else
-typedef pthread_cond_t  cnd_t;
-typedef pthread_t       thrd_t;
-typedef pthread_key_t   tss_t;
-typedef pthread_mutex_t mtx_t;
-typedef pthread_once_t  once_flag;
-// FIXME: temporary non-standard hack to ease transition
-#    define KIT_MTX_INITIALIZER_NP_ PTHREAD_MUTEX_INITIALIZER
-#    define ONCE_FLAG_INIT PTHREAD_ONCE_INIT
-#    ifdef PTHREAD_DESTRUCTOR_ITERATIONS
-#      define TSS_DTOR_ITERATIONS PTHREAD_DESTRUCTOR_ITERATIONS
-#    else
-#      define TSS_DTOR_ITERATIONS \
-        1 // assume TSS dtor MAY be called at least once.
-#    endif
-#  endif
-
-/*-------------------- enumeration constants --------------------*/
-enum {
-  mtx_plain     = 0,
-  mtx_recursive = 1,
-  mtx_timed     = 2,
-};
-
-enum {
-  thrd_success = 0, // succeeded
-  thrd_timedout,    // timed out
-  thrd_error,       // failed
-  thrd_busy,        // resource busy
-  thrd_nomem,       // out of memory,
-  thrd_wrong_stack_size
-};
-
-/*-------------------------- functions --------------------------*/
-
-void   call_once(once_flag *, void (*)(void));
-int    cnd_broadcast(cnd_t *);
-void   cnd_destroy(cnd_t *);
-int    cnd_init(cnd_t *);
-int    cnd_signal(cnd_t *);
-int    cnd_timedwait(cnd_t *__restrict, mtx_t *__restrict mtx_,
-                     const struct timespec *__restrict);
-int    cnd_wait(cnd_t *, mtx_t *mtx_);
-void   mtx_destroy(mtx_t *mtx_);
-int    mtx_init(mtx_t *mtx_, int);
-int    mtx_lock(mtx_t *mtx_);
-int    mtx_timedlock(mtx_t *__restrict mtx_,
-                     const struct timespec *__restrict);
-int    mtx_trylock(mtx_t *mtx_);
-int    mtx_unlock(mtx_t *mtx_);
-int    thrd_create(thrd_t *, thrd_start_t, void *);
-int    thrd_create_with_stack(thrd_t *, thrd_start_t, void *,
-                              ptrdiff_t stack_size);
-thrd_t thrd_current(void);
-int    thrd_detach(thrd_t);
-int    thrd_equal(thrd_t, thrd_t);
-#  if defined(__cplusplus)
-[[ noreturn ]]
-#  else
-_Noreturn
-#  endif
-void thrd_exit(int);
-int  thrd_join(thrd_t, int *);
-int  thrd_sleep(const struct timespec *, struct timespec *);
-void thrd_yield(void);
-
-#  ifdef __cplusplus
-}
-#  endif
-
-#endif /* KIT_DISABLE_SYSTEM_THREADS */
-
-#endif /* KIT_THREADS_H */
diff --git a/source/kit/time.c b/source/kit/time.c
index bcb3819..108434f 100644
--- a/source/kit/time.c
+++ b/source/kit/time.c
@@ -1,39 +1,6 @@
-/*
- * C11 <time.h> implementation
- *
- * (C) Copyright yohhoy 2012.
- * Copyright 2022 Yonggang Luo
- * Distributed under the Boost Software License, Version 1.0.
- *
- * Permission is hereby granted, free of charge, to any person or
- * organization obtaining a copy of the software and accompanying
- * documentation covered by this license (the "Software") to use,
- * reproduce, display, distribute, execute, and transmit the Software,
- * and to prepare [[derivative work]]s of the Software, and to permit
- * third-parties to whom the Software is furnished to do so, all
- * subject to the following:
- *
- * The copyright notices in the Software and this entire statement,
- * including the above license grant, this restriction and the
- * following disclaimer, must be included in all copies of the
- * Software, in whole or in part, and all derivative works of the
- * Software, unless such copies or derivative works are solely in the
- * form of machine-executable object code generated by a source
- * language processor.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
- * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE
- * DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER
- * LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
-
 #include "time.h"
 
-#ifndef KIT_HAVE_TIMESPEC_GET
+#ifdef KIT_NEED_TIMESPEC_GET
 
 #  if defined(_WIN32) && !defined(__CYGWIN__)
 
@@ -43,11 +10,11 @@
 #    include <windows.h>
 
 int timespec_get(struct timespec *ts, int base) {
-/* difference between 1970 and 1601 */
+/*  difference between 1970 and 1601 */
 #    define _TIMESPEC_IMPL_UNIX_EPOCH_IN_TICKS 116444736000000000ull
-/* 1 tick is 100 nanoseconds */
+/*  1 tick is 100 nanoseconds */
 #    define _TIMESPEC_IMPL_TICKS_PER_SECONDS 10000000ull
-  if (!ts)
+  if (ts == NULL)
     return 0;
   if (base == TIME_UTC) {
     FILETIME       ft;
@@ -71,7 +38,7 @@ int timespec_get(struct timespec *ts, int base) {
 #  else
 
 int timespec_get(struct timespec *ts, int base) {
-  if (!ts)
+  if (ts == NULL)
     return 0;
   if (base == TIME_UTC) {
     clock_gettime(CLOCK_REALTIME, ts);
diff --git a/source/kit/time.h b/source/kit/time.h
index 0d995f4..9445912 100644
--- a/source/kit/time.h
+++ b/source/kit/time.h
@@ -1,17 +1,8 @@
-/*
- * Copyright 2022 Yonggang Luo
- * SPDX-License-Identifier: MIT
- *
- * C11 <time.h> emulation library
- */
-
 #ifndef KIT_TIME_H
 #define KIT_TIME_H
 
 #include <time.h>
 
-/*---------------------------- macros ---------------------------*/
-
 #ifndef TIME_UTC
 #  define TIME_UTC 1
 #endif
@@ -20,43 +11,19 @@
 extern "C" {
 #endif
 
-/*---------------------------- types ----------------------------*/
-
-/*
- * On MINGW `struct timespec` present but `timespec_get` may not
- * present; On MSVC `struct timespec` and `timespec_get` present at
- * the same time; So detecting `HAVE_STRUCT_TIMESPEC` in meson script
- * dynamically.
- */
-#ifndef KIT_HAVE_STRUCT_TIMESPEC
+#ifdef KIT_NEED_STRUCT_TIMESPEC
 struct timespec {
-  time_t tv_sec;  // Seconds - >= 0
-  long   tv_nsec; // Nanoseconds - [0, 999999999]
+  time_t tv_sec;  /* Seconds      - >= 0 */
+  long   tv_nsec; /* Nanoseconds  - [0, 999999999] */
 };
 #endif
 
-/*-------------------------- functions --------------------------*/
-
-#if !defined(KIT_HAVE_TIMESPEC_GET)
-#  define KIT_TIMESPEC_GET_NEED_DECL_
-#elif defined(__APPLE__) && defined(__cplusplus) && \
-    (__cplusplus < 201703L)
-/* On macOS, the guard for declaration of timespec_get is by
- * (defined(__cplusplus) && __cplusplus >= 201703L),
- * fix the declaration for C++14 and lower here
- */
-#  define KIT_TIMESPEC_GET_NEED_DECL_
-#endif
-
-#ifdef KIT_TIMESPEC_GET_NEED_DECL_
-/*-------------------- 7.25.7 Time functions --------------------*/
-// 7.25.6.1
+#ifdef KIT_NEED_TIMESPEC_GET
 int timespec_get(struct timespec *ts, int base);
-#  undef KIT_TIMESPEC_GET_NEED_DECL_
 #endif
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* KIT_TIME_H */
+#endif
diff --git a/source/test/unittests/atomic.test.c b/source/test/unittests/atomic.test.c
index c909cb0..b8cf0ac 100644
--- a/source/test/unittests/atomic.test.c
+++ b/source/test/unittests/atomic.test.c
@@ -1,5 +1,5 @@
 #include "../../kit/atomic.h"
-#include "../../kit/threads.h"
+#include "../../kit/thread.h"
 
 #define KIT_TEST_FILE atomic
 #include "../../kit_test/test.h"
diff --git a/source/test/unittests/condition_variable.test.c b/source/test/unittests/condition_variable.test.c
index c855b0c..c5b0468 100644
--- a/source/test/unittests/condition_variable.test.c
+++ b/source/test/unittests/condition_variable.test.c
@@ -1,4 +1,5 @@
 #include "../../kit/condition_variable.h"
+#include "../../kit/thread.h"
 
 #define KIT_TEST_FILE condition_variable
 #include "../../kit_test/test.h"
diff --git a/source/test/unittests/mersenne_twister_64.test.c b/source/test/unittests/mersenne_twister_64.test.c
index b986c55..80d1c2c 100644
--- a/source/test/unittests/mersenne_twister_64.test.c
+++ b/source/test/unittests/mersenne_twister_64.test.c
@@ -1,4 +1,5 @@
 #include "../../kit/mersenne_twister_64.h"
+#include "../../kit/secure_random.h"
 
 #define KIT_TEST_FILE mersenne_twister_64
 #include "../../kit_test/test.h"
@@ -6,7 +7,8 @@
 enum { SIZE = 1000 };
 
 TEST("mt64 same seeds") {
-  uint64_t seed = mt64_seed();
+  uint64_t seed;
+  secure_random(sizeof seed, &seed);
 
   mt64_state_t foo, bar;
   mt64_init(&foo, seed);
diff --git a/source/test/unittests/mutex.test.c b/source/test/unittests/mutex.test.c
index a898557..e597e59 100644
--- a/source/test/unittests/mutex.test.c
+++ b/source/test/unittests/mutex.test.c
@@ -1,4 +1,5 @@
 #include "../../kit/mutex.h"
+#include "../../kit/thread.h"
 
 #define KIT_TEST_FILE mutex
 #include "../../kit_test/test.h"
diff --git a/source/test/unittests/secure_random.test.c b/source/test/unittests/secure_random.test.c
index eadae65..ec0a7b2 100644
--- a/source/test/unittests/secure_random.test.c
+++ b/source/test/unittests/secure_random.test.c
@@ -8,13 +8,9 @@ TEST("secure random") {
   int v[20];
   memset(v, 0, sizeof v);
 
-  secure_random_init();
-
   secure_random(40, v);
   secure_random(40, v + 10);
 
-  secure_random_cleanup();
-
   int repeats = 0;
 
   for (int i = 1; i < sizeof v / sizeof *v; i++)
diff --git a/source/test/unittests/thread.test.c b/source/test/unittests/thread.test.c
index 786e992..01198c2 100644
--- a/source/test/unittests/thread.test.c
+++ b/source/test/unittests/thread.test.c
@@ -1,4 +1,4 @@
-#include "../../kit/threads.h"
+#include "../../kit/thread.h"
 
 #define KIT_TEST_FILE thread
 #include "../../kit_test/test.h"