Class Logger#

Inheritance Relationships#

Base Type#

  • public QObject

Class Documentation#

class Logger : public QObject

Thread-safe application logger with file output and a Qt signal.

Logger is a singleton — access it via Logger::instance(). In practice, prefer the free functions (log_info, log_error, …) which automatically capture the call site via std::source_location.

Connecting the UI panel
// In LoggerPanelW constructor (main thread):
connect(&Logger::instance(), &Logger::entry_added,
        this, &LoggerPanelW::on_entry_added,
        Qt::QueuedConnection);   // ← always use QueuedConnection

Note

The entry_added() signal is emitted from the calling thread. Always use Qt::QueuedConnection when connecting to a main-thread slot from a background worker.

Public Functions

~Logger() override
void log(LogLevel level, const QString &message, std::source_location loc = std::source_location::current())

Logs a message at the given severity level.

Thread-safe. If a log file is open, the message is written to it (mutex-protected). entry_added() is then emitted from the calling thread.

Parameters:

  • level – Severity level.

  • message – UTF-8 message string.

  • loc – Automatically-captured source location — do not pass manually.

void set_min_level(LogLevel level)

Sets the minimum level written to file and emitted via signal.

Messages below this level are discarded. Default: LogLevel::Trace.

Parameters:

level – New minimum level.

bool open_log_file(const QString &path)

Opens a log file for writing (appending if it already exists).

Parameters:

path – Absolute file path.

Returns:

true on success.

void close_log_file()

Flushes and closes the log file.

Signals

void entry_added(int level, QString timestamp, QString location, QString message)

Emitted for every accepted log entry, from the calling thread.

Parameters:

  • level – Severity as int — cast back with static_cast<LogLevel>(level).

  • timestamp – Wall-clock string, e.g. "14:32:05.123".

  • location – Source location, e.g. "record_manager.cpp:88".

  • message – The log message.

Public Static Functions

static Logger &instance()
Returns:

The process-wide Logger singleton.