20 files changed, 232 insertions, 48 deletions
diff --git a/src/libcamera/base/backtrace.cpp b/src/libcamera/base/backtrace.cpp
index 483492c3..0b04629c 100644
--- a/src/libcamera/base/backtrace.cpp
+++ b/src/libcamera/base/backtrace.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2021, Ideas on Board Oy
  *
- * backtrace.h - Call stack backtraces
+ * Call stack backtraces
  */
 
 #include <libcamera/base/backtrace.h>
@@ -191,10 +191,22 @@ __attribute__((__noinline__))
 bool Backtrace::unwindTrace()
 {
 #if HAVE_UNWIND
+/*
+ * unw_getcontext() for ARM32 is an inline assembly function using the stmia
+ * instruction to store SP and PC. This is considered by clang-11 as deprecated,
+ * and generates a warning.
+ */
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Winline-asm"
+#endif
 	unw_context_t uc;
 	int ret = unw_getcontext(&uc);
 	if (ret)
 		return false;
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
 
 	unw_cursor_t cursor;
 	ret = unw_init_local(&cursor, &uc);
diff --git a/src/libcamera/base/bound_method.cpp b/src/libcamera/base/bound_method.cpp
index 3ecec51c..322029a8 100644
--- a/src/libcamera/base/bound_method.cpp
+++ b/src/libcamera/base/bound_method.cpp
@@ -2,11 +2,12 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * bound_method.cpp - Method bind and invocation
+ * Method bind and invocation
  */
 
 #include <libcamera/base/bound_method.h>
 #include <libcamera/base/message.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/semaphore.h>
 #include <libcamera/base/thread.h>
 
diff --git a/src/libcamera/base/class.cpp b/src/libcamera/base/class.cpp
index 9c2d9f21..61998398 100644
--- a/src/libcamera/base/class.cpp
+++ b/src/libcamera/base/class.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2020, Google Inc.
  *
- * class.cpp - Utilities and helpers for classes
+ * Utilities and helpers for classes
  */
 
 #include <libcamera/base/class.h>
diff --git a/src/libcamera/base/event_dispatcher.cpp b/src/libcamera/base/event_dispatcher.cpp
index 4be89e81..5f4a5cb4 100644
--- a/src/libcamera/base/event_dispatcher.cpp
+++ b/src/libcamera/base/event_dispatcher.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * event_dispatcher.cpp - Event dispatcher
+ * Event dispatcher
  */
 
 #include <libcamera/base/event_dispatcher.h>
diff --git a/src/libcamera/base/event_dispatcher_poll.cpp b/src/libcamera/base/event_dispatcher_poll.cpp
index 7238a316..b737ca7a 100644
--- a/src/libcamera/base/event_dispatcher_poll.cpp
+++ b/src/libcamera/base/event_dispatcher_poll.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * event_dispatcher_poll.cpp - Poll-based event dispatcher
+ * Poll-based event dispatcher
  */
 
 #include <libcamera/base/event_dispatcher_poll.h>
diff --git a/src/libcamera/base/event_notifier.cpp b/src/libcamera/base/event_notifier.cpp
index fd93c087..495c281d 100644
--- a/src/libcamera/base/event_notifier.cpp
+++ b/src/libcamera/base/event_notifier.cpp
@@ -2,12 +2,13 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * event_notifier.cpp - File descriptor event notifier
+ * File descriptor event notifier
  */
 
 #include <libcamera/base/event_notifier.h>
 
 #include <libcamera/base/event_dispatcher.h>
+#include <libcamera/base/log.h>
 #include <libcamera/base/message.h>
 #include <libcamera/base/thread.h>
 
@@ -20,6 +21,8 @@
 
 namespace libcamera {
 
+LOG_DECLARE_CATEGORY(Event)
+
 /**
  * \class EventNotifier
  * \brief Notify of activity on a file descriptor
@@ -104,6 +107,9 @@ EventNotifier::~EventNotifier()
  */
 void EventNotifier::setEnabled(bool enable)
 {
+	if (!assertThreadBound("EventNotifier can't be enabled from another thread"))
+		return;
+
 	if (enabled_ == enable)
 		return;
 
diff --git a/src/libcamera/base/file.cpp b/src/libcamera/base/file.cpp
index fb3e276d..2b83a517 100644
--- a/src/libcamera/base/file.cpp
+++ b/src/libcamera/base/file.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2020, Google Inc.
  *
- * file.cpp - File I/O operations
+ * File I/O operations
  */
 
 #include <libcamera/base/file.h>
@@ -163,6 +163,9 @@ bool File::exists() const
  * attempt to create the file with initial permissions set to 0666 (modified by
  * the process' umask).
  *
+ * The file is opened with the O_CLOEXEC flag, and will be closed automatically
+ * when a new binary is executed with one of the exec(3) functions.
+ *
  * The error() status is updated.
  *
  * \return True on success, false otherwise
@@ -178,7 +181,7 @@ bool File::open(File::OpenMode mode)
 	if (mode & OpenModeFlag::WriteOnly)
 		flags |= O_CREAT;
 
-	fd_ = UniqueFD(::open(name_.c_str(), flags, 0666));
+	fd_ = UniqueFD(::open(name_.c_str(), flags | O_CLOEXEC, 0666));
 	if (!fd_.isValid()) {
 		error_ = -errno;
 		return false;
diff --git a/src/libcamera/base/flags.cpp b/src/libcamera/base/flags.cpp
index 3e4320ac..9981f2ed 100644
--- a/src/libcamera/base/flags.cpp
+++ b/src/libcamera/base/flags.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2020, Google Inc.
  *
- * flags.cpp - Type-safe enum-based bitfields
+ * Type-safe enum-based bitfields
  */
 
 #include <libcamera/base/flags.h>
diff --git a/src/libcamera/base/log.cpp b/src/libcamera/base/log.cpp
index 5c359a22..3a656b8f 100644
--- a/src/libcamera/base/log.cpp
+++ b/src/libcamera/base/log.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2018, Google Inc.
  *
- * log.cpp - Logging infrastructure
+ * Logging infrastructure
  */
 
 #include <libcamera/base/log.h>
@@ -21,6 +21,7 @@
 #include <libcamera/logging.h>
 
 #include <libcamera/base/backtrace.h>
+#include <libcamera/base/mutex.h>
 #include <libcamera/base/thread.h>
 #include <libcamera/base/utils.h>
 
@@ -314,10 +315,11 @@ private:
 
 	friend LogCategory;
 	void registerCategory(LogCategory *category);
+	LogCategory *findCategory(const char *name) const;
 
 	static bool destroyed_;
 
-	std::unordered_set<LogCategory *> categories_;
+	std::vector<LogCategory *> categories_;
 	std::list<std::pair<std::string, LogSeverity>> levels_;
 
 	std::shared_ptr<LogOutput> output_;
@@ -568,7 +570,7 @@ void Logger::logSetLevel(const char *category, const char *level)
 		return;
 
 	for (LogCategory *c : categories_) {
-		if (!strcmp(c->name(), category)) {
+		if (c->name() == category) {
 			c->setSeverity(severity);
 			break;
 		}
@@ -707,12 +709,12 @@ LogSeverity Logger::parseLogLevel(const std::string &level)
  * \brief Register a log category with the logger
  * \param[in] category The log category
  *
- * Log categories must have unique names. If a category with the same name
- * already exists this function performs no operation.
+ * Log categories must have unique names. It is invalid to call this function
+ * if a log category with the same name already exists.
  */
 void Logger::registerCategory(LogCategory *category)
 {
-	categories_.insert(category);
+	categories_.push_back(category);
 
 	const std::string &name = category->name();
 	for (const std::pair<std::string, LogSeverity> &level : levels_) {
@@ -737,6 +739,22 @@ void Logger::registerCategory(LogCategory *category)
 }
 
 /**
+ * \brief Find an existing log category with the given name
+ * \param[in] name Name of the log category
+ * \return The pointer to the found log category or nullptr if not found
+ */
+LogCategory *Logger::findCategory(const char *name) const
+{
+	if (auto it = std::find_if(categories_.begin(), categories_.end(),
+				   [name](auto c) { return c->name() == name; });
+	    it != categories_.end()) {
+		return *it;
+	}
+
+	return nullptr;
+}
+
+/**
  * \enum LogSeverity
  * Log message severity
  * \var LogDebug
@@ -761,13 +779,35 @@ void Logger::registerCategory(LogCategory *category)
  */
 
 /**
+ * \brief Create a new LogCategory or return an existing one
+ * \param[in] name Name of the log category
+ *
+ * Create and return a new LogCategory with the given name if such a category
+ * does not yet exist, or return the existing one.
+ *
+ * \return The pointer to the LogCategory
+ */
+LogCategory *LogCategory::create(const char *name)
+{
+	static Mutex mutex_;
+	MutexLocker locker(mutex_);
+	LogCategory *category = Logger::instance()->findCategory(name);
+
+	if (!category) {
+		category = new LogCategory(name);
+		Logger::instance()->registerCategory(category);
+	}
+
+	return category;
+}
+
+/**
  * \brief Construct a log category
  * \param[in] name The category name
  */
 LogCategory::LogCategory(const char *name)
 	: name_(name), severity_(LogSeverity::LogInfo)
 {
-	Logger::instance()->registerCategory(this);
 }
 
 /**
@@ -804,7 +844,7 @@ void LogCategory::setSeverity(LogSeverity severity)
  */
 const LogCategory &LogCategory::defaultCategory()
 {
-	static const LogCategory *category = new LogCategory("default");
+	static const LogCategory *category = LogCategory::create("default");
 	return *category;
 }
 
diff --git a/src/libcamera/base/meson.build b/src/libcamera/base/meson.build
index 7030ad1f..7a7fd7e4 100644
--- a/src/libcamera/base/meson.build
+++ b/src/libcamera/base/meson.build
@@ -22,8 +22,8 @@ libcamera_base_sources = files([
     'utils.cpp',
 ])
 
-libdw = cc.find_library('libdw', required : false)
-libunwind = cc.find_library('libunwind', required : false)
+libdw = dependency('libdw', required : false)
+libunwind = dependency('libunwind', required : false)
 
 if cc.has_header_symbol('execinfo.h', 'backtrace')
     config_h.set('HAVE_BACKTRACE', 1)
@@ -38,9 +38,9 @@ if libunwind.found()
 endif
 
 libcamera_base_deps = [
-    dependency('threads'),
     libatomic,
     libdw,
+    libthreads,
     libunwind,
 ]
 
@@ -51,6 +51,7 @@ libcamera_base_args = [ '-DLIBCAMERA_BASE_PRIVATE' ]
 libcamera_base_lib = shared_library('libcamera-base',
                                     [libcamera_base_sources, libcamera_base_headers],
                                     version : libcamera_version,
+                                    soversion : libcamera_soversion,
                                     name_prefix : '',
                                     install : true,
                                     cpp_args : libcamera_base_args,
diff --git a/src/libcamera/base/message.cpp b/src/libcamera/base/message.cpp
index 2da2a7ed..098faac6 100644
--- a/src/libcamera/base/message.cpp
+++ b/src/libcamera/base/message.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * message.cpp - Message queue support
+ * Message queue support
  */
 
 #include <libcamera/base/message.h>
diff --git a/src/libcamera/base/mutex.cpp b/src/libcamera/base/mutex.cpp
index e34e8618..2a4542c4 100644
--- a/src/libcamera/base/mutex.cpp
+++ b/src/libcamera/base/mutex.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2021, Google Inc.
  *
- * mutex.cpp - Mutex classes with clang thread safety annotation
+ * Mutex classes with clang thread safety annotation
  */
 
 #include <libcamera/base/mutex.h>
diff --git a/src/libcamera/base/object.cpp b/src/libcamera/base/object.cpp
index 92cecd22..745d2565 100644
--- a/src/libcamera/base/object.cpp
+++ b/src/libcamera/base/object.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * object.cpp - Base object
+ * Base object
  */
 
 #include <libcamera/base/object.h>
@@ -40,8 +40,9 @@ LOG_DEFINE_CATEGORY(Object)
  * Object class.
  *
  * Deleting an object from a thread other than the one the object is bound to is
- * unsafe, unless the caller ensures that the object isn't processing any
- * message concurrently.
+ * unsafe, unless the caller ensures that the object's thread is stopped and no
+ * parent or child of the object gets deleted concurrently. See
+ * Object::~Object() for more information.
  *
  * Object slots connected to signals will also run in the context of the
  * object's thread, regardless of whether the signal is emitted in the same or
@@ -84,9 +85,20 @@ Object::Object(Object *parent)
  * Object instances shall be destroyed from the thread they are bound to,
  * otherwise undefined behaviour may occur. If deletion of an Object needs to
  * be scheduled from a different thread, deleteLater() shall be used.
+ *
+ * As an exception to this rule, Object instances may be deleted from a
+ * different thread if the thread the instance is bound to is stopped through
+ * the whole duration of the object's destruction, *and* the parent and children
+ * of the object do not get deleted concurrently. The caller is responsible for
+ * fulfilling those requirements.
+ *
+ * In all cases Object instances shall be deleted before the Thread they are
+ * bound to.
  */
 Object::~Object()
 {
+	ASSERT(Thread::current() == thread_ || !thread_->isRunning());
+
 	/*
 	 * Move signals to a private list to avoid concurrent iteration and
 	 * deletion of items from Signal::disconnect().
@@ -116,8 +128,9 @@ Object::~Object()
  * event loop that the object belongs to. This ensures the object is destroyed
  * from the right context, as required by the libcamera threading model.
  *
- * If this function is called before the thread's event loop is started, the
- * object will be deleted when the event loop starts.
+ * If this function is called before the thread's event loop is started or after
+ * it has stopped, the object will be deleted when the event loop (re)starts. If
+ * this never occurs, the object will be leaked.
  *
  * Deferred deletion can be used to control the destruction context with shared
  * pointers. An object managed with shared pointers is deleted when the last
@@ -213,6 +226,35 @@ void Object::message(Message *msg)
 }
 
 /**
+ * \fn Object::assertThreadBound()
+ * \brief Check if the caller complies with thread-bound constraints
+ * \param[in] message The message to be printed on error
+ *
+ * This function verifies the calling constraints required by the \threadbound
+ * definition. It shall be called at the beginning of member functions of an
+ * Object subclass that are explicitly marked as thread-bound in their
+ * documentation.
+ *
+ * If the thread-bound constraints are not met, the function prints \a message
+ * as an error message. For debug builds, it additionally causes an assertion
+ * error.
+ *
+ * \todo Verify the thread-bound requirements for functions marked as
+ * thread-bound at the class level.
+ *
+ * \return True if the call is thread-bound compliant, false otherwise
+ */
+bool Object::assertThreadBound(const char *message)
+{
+	if (Thread::current() == thread_)
+		return true;
+
+	LOG(Object, Error) << message;
+	ASSERT(false);
+	return false;
+}
+
+/**
  * \fn R Object::invokeMethod()
  * \brief Invoke a method asynchronously on an Object instance
  * \param[in] func The object method to invoke
@@ -259,11 +301,12 @@ void Object::message(Message *msg)
  * Moving an object that has a parent is not allowed, and causes undefined
  * behaviour.
  *
- * \context This function is thread-bound.
+ * \context This function is \threadbound.
  */
 void Object::moveToThread(Thread *thread)
 {
-	ASSERT(Thread::current() == thread_);
+	if (!assertThreadBound("Object can't be moved from another thread"))
+		return;
 
 	if (thread_ == thread)
 		return;
diff --git a/src/libcamera/base/semaphore.cpp b/src/libcamera/base/semaphore.cpp
index 4fe30293..862f3b31 100644
--- a/src/libcamera/base/semaphore.cpp
+++ b/src/libcamera/base/semaphore.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * semaphore.cpp - General-purpose counting semaphore
+ * General-purpose counting semaphore
  */
 
 #include <libcamera/base/semaphore.h>
@@ -56,7 +56,9 @@ unsigned int Semaphore::available()
 void Semaphore::acquire(unsigned int n)
 {
 	MutexLocker locker(mutex_);
-	cv_.wait(locker, [&] { return available_ >= n; });
+	cv_.wait(locker, [&]() LIBCAMERA_TSA_REQUIRES(mutex_) {
+		return available_ >= n;
+	});
 	available_ -= n;
 }
 
diff --git a/src/libcamera/base/shared_fd.cpp b/src/libcamera/base/shared_fd.cpp
index c711cf57..7afc8ca5 100644
--- a/src/libcamera/base/shared_fd.cpp
+++ b/src/libcamera/base/shared_fd.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * shared_fd.cpp - File descriptor wrapper with shared ownership
+ * File descriptor wrapper with shared ownership
  */
 
 #include <libcamera/base/shared_fd.h>
diff --git a/src/libcamera/base/signal.cpp b/src/libcamera/base/signal.cpp
index a46386a0..b782e050 100644
--- a/src/libcamera/base/signal.cpp
+++ b/src/libcamera/base/signal.cpp
@@ -2,12 +2,13 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * signal.cpp - Signal & slot implementation
+ * Signal & slot implementation
  */
 
 #include <libcamera/base/signal.h>
 
 #include <libcamera/base/mutex.h>
+#include <libcamera/base/object.h>
 
 /**
  * \file base/signal.h
@@ -74,7 +75,7 @@ SignalBase::SlotList SignalBase::slots()
  *
  * Signals and slots are a language construct aimed at communication between
  * objects through the observer pattern without the need for boilerplate code.
- * See http://doc.qt.io/qt-5/signalsandslots.html for more information.
+ * See http://doc.qt.io/qt-6/signalsandslots.html for more information.
  *
  * Signals model events that can be observed from objects unrelated to the event
  * source. Slots are functions that are called in response to a signal. Signals
diff --git a/src/libcamera/base/thread.cpp b/src/libcamera/base/thread.cpp
index 6bda9d14..72733431 100644
--- a/src/libcamera/base/thread.cpp
+++ b/src/libcamera/base/thread.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * thread.cpp - Thread support
+ * Thread support
  */
 
 #include <libcamera/base/thread.h>
@@ -18,6 +18,7 @@
 #include <libcamera/base/log.h>
 #include <libcamera/base/message.h>
 #include <libcamera/base/mutex.h>
+#include <libcamera/base/object.h>
 
 /**
  * \page thread Thread Support
@@ -151,7 +152,7 @@ private:
 	friend class ThreadMain;
 
 	Thread *thread_;
-	bool running_;
+	bool running_ LIBCAMERA_TSA_GUARDED_BY(mutex_);
 	pid_t tid_;
 
 	Mutex mutex_;
@@ -370,6 +371,12 @@ void Thread::run()
 
 void Thread::finishThread()
 {
+	/*
+	 * Objects may have been scheduled for deletion right before the thread
+	 * exited. Ensure they get deleted now, before the thread stops.
+	 */
+	dispatchMessages(Message::Type::DeferredDelete);
+
 	data_->mutex_.lock();
 	data_->running_ = false;
 	data_->mutex_.unlock();
@@ -422,11 +429,15 @@ bool Thread::wait(utils::duration duration)
 	{
 		MutexLocker locker(data_->mutex_);
 
+		auto isRunning = ([&]() LIBCAMERA_TSA_REQUIRES(data_->mutex_) {
+			return !data_->running_;
+		});
+
 		if (duration == utils::duration::max())
-			data_->cv_.wait(locker, [&]() { return !data_->running_; });
+			data_->cv_.wait(locker, isRunning);
 		else
 			hasFinished = data_->cv_.wait_for(locker, duration,
-							  [&]() { return !data_->running_; });
+							  isRunning);
 	}
 
 	if (thread_.joinable())
diff --git a/src/libcamera/base/timer.cpp b/src/libcamera/base/timer.cpp
index 74b060af..7b0f3725 100644
--- a/src/libcamera/base/timer.cpp
+++ b/src/libcamera/base/timer.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * timer.cpp - Generic timer
+ * Generic timer
  */
 
 #include <libcamera/base/timer.h>
@@ -85,10 +85,8 @@ void Timer::start(std::chrono::milliseconds duration)
  */
 void Timer::start(std::chrono::steady_clock::time_point deadline)
 {
-	if (Thread::current() != thread()) {
-		LOG(Timer, Error) << "Timer " << this << " << can't be started from another thread";
+	if (!assertThreadBound("Timer can't be started from another thread"))
 		return;
-	}
 
 	deadline_ = deadline;
 
@@ -114,13 +112,11 @@ void Timer::start(std::chrono::steady_clock::time_point deadline)
  */
 void Timer::stop()
 {
-	if (!isRunning())
+	if (!assertThreadBound("Timer can't be stopped from another thread"))
 		return;
 
-	if (Thread::current() != thread()) {
-		LOG(Timer, Error) << "Timer " << this << " can't be stopped from another thread";
+	if (!isRunning())
 		return;
-	}
 
 	unregisterTimer();
 }
diff --git a/src/libcamera/base/unique_fd.cpp b/src/libcamera/base/unique_fd.cpp
index 83d6919c..d0649e4d 100644
--- a/src/libcamera/base/unique_fd.cpp
+++ b/src/libcamera/base/unique_fd.cpp
@@ -2,7 +2,7 @@
 /*
  * Copyright (C) 2021, Google Inc.
  *
- * unique_fd.cpp - File descriptor wrapper that owns a file descriptor
+ * File descriptor wrapper that owns a file descriptor
  */
 
 #include <libcamera/base/unique_fd.h>
diff --git a/src/libcamera/base/utils.cpp b/src/libcamera/base/utils.cpp
index 6a307940..ccb31063 100644
--- a/src/libcamera/base/utils.cpp
+++ b/src/libcamera/base/utils.cpp
@@ -2,12 +2,13 @@
 /*
  * Copyright (C) 2019, Google Inc.
  *
- * utils.cpp - Miscellaneous utility functions
+ * Miscellaneous utility functions
  */
 
 #include <libcamera/base/utils.h>
 
 #include <iomanip>
+#include <locale.h>
 #include <sstream>
 #include <stdlib.h>
 #include <string.h>
@@ -463,6 +464,73 @@ std::string toAscii(const std::string &str)
  * \a b
  */
 
+#if HAVE_LOCALE_T
+
+namespace {
+
+/*
+ * RAII wrapper around locale_t instances, to support global locale instances
+ * without leaking memory.
+ */
+class Locale
+{
+public:
+	Locale(const char *locale)
+	{
+		locale_ = newlocale(LC_ALL_MASK, locale, static_cast<locale_t>(0));
+	}
+
+	~Locale()
+	{
+		freelocale(locale_);
+	}
+
+	locale_t locale() { return locale_; }
+
+private:
+	locale_t locale_;
+};
+
+Locale cLocale("C");
+
+} /* namespace */
+
+#endif /* HAVE_LOCALE_T */
+
+/**
+ * \brief Convert a string to a double independently of the current locale
+ * \param[in] nptr The string to convert
+ * \param[out] endptr Pointer to trailing portion of the string after conversion
+ *
+ * This function is a locale-independent version of the std::strtod() function.
+ * It behaves as the standard function, but uses the "C" locale instead of the
+ * current locale.
+ *
+ * \return The converted value, if any, or 0.0 if the conversion failed.
+ */
+double strtod(const char *__restrict nptr, char **__restrict endptr)
+{
+#if HAVE_LOCALE_T
+	return strtod_l(nptr, endptr, cLocale.locale());
+#else
+	/*
+	 * If the libc implementation doesn't provide locale object support,
+	 * assume that strtod() is locale-independent.
+	 */
+	return ::strtod(nptr, endptr);
+#endif
+}
+
+/**
+ * \fn to_underlying(Enum e)
+ * \brief Convert an enumeration to its underlygin type
+ * \param[in] e Enumeration value to convert
+ *
+ * This function is equivalent to the C++23 std::to_underlying().
+ *
+ * \return The value of e converted to its underlying type
+ */
+
 } /* namespace utils */
 
 #ifndef __DOXYGEN__