qtlogger

QtLogger Docs > API Reference

API Reference

This section provides detailed documentation for all QtLogger classes and their APIs.

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Table of Contents

Core Classes

• Core — Fundamental classes for logging
  • Logger — The main logger class and global instance
  • LogMessage — Container for log message data
  • Utility functions

Pipeline Classes

• Pipelines — Message processing pipelines
  • Pipeline — Base pipeline class
  • SortedPipeline — Auto-sorting pipeline by handler type
  • SimplePipeline — Fluent API pipeline

Handler Classes

• Sinks — Output destinations
  • StdOutSink / StdErrSink — Console output
  • FileSink / RotatingFileSink — File output
  • HttpSink — HTTP endpoint
  • SyslogSink / SdJournalSink — System logs
  • AndroidLogSink / OslogSink — Mobile platforms
  • SignalSink — Qt signals
  • WinDebugSink — Windows debug output
• Formatters — Message formatting
  • PatternFormatter — Pattern-based formatting
  • JsonFormatter — JSON output
  • PrettyFormatter — Human-readable colored output
  • QtLogMessageFormatter — Qt default formatting
  • FunctionFormatter — Custom function-based formatting
• Filters — Message filtering
  • LevelFilter — Filter by severity
  • CategoryFilter — Filter by Qt category
  • RegExpFilter — Filter by regex
  • DuplicateFilter — Suppress duplicates
  • FunctionFilter — Custom function-based filtering
• Attribute Handlers — Message enrichment
  • SeqNumberAttr — Sequential numbering
  • AppInfoAttrs — Application metadata
  • AppUuidAttr — Persistent application UUID
  • SysInfoAttrs — System information
  • HostInfoAttrs — Host information
  • FunctionAttrHandler — Custom attributes

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Class Hierarchy

Handler (abstract)
├── AttrHandler (abstract)
│   ├── SeqNumberAttr
│   ├── AppInfoAttrs
│   ├── AppUuidAttr
│   ├── SysInfoAttrs
│   ├── HostInfoAttrs
│   └── FunctionAttrHandler
├── Filter (abstract)
│   ├── LevelFilter
│   ├── CategoryFilter
│   ├── RegExpFilter
│   ├── DuplicateFilter
│   └── FunctionFilter
├── Formatter (abstract)
│   ├── PatternFormatter
│   ├── JsonFormatter
│   ├── PrettyFormatter
│   ├── QtLogMessageFormatter
│   └── FunctionFormatter
├── Sink (abstract)
│   ├── IODeviceSink
│   │   └── FileSink
│   │       └── RotatingFileSink
│   ├── StdOutSink
│   ├── StdErrSink
│   ├── HttpSink
│   ├── SyslogSink
│   ├── SdJournalSink
│   ├── AndroidLogSink
│   ├── OslogSink
│   ├── SignalSink
│   └── WinDebugSink
├── Pipeline
│   └── SortedPipeline
│       └── SimplePipeline
│           └── Logger
└── FunctionHandler

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Smart Pointer Types

All handler classes have corresponding smart pointer typedefs:

Class	Pointer Type
Handler	HandlerPtr
AttrHandler	AttrHandlerPtr
Filter	FilterPtr
Formatter	FormatterPtr
Sink	SinkPtr
Pipeline	PipelinePtr
Logger	(singleton, use gQtLogger)
LevelFilter	LevelFilterPtr
PatternFormatter	PatternFormatterPtr
StdErrSink	StdErrSinkPtr
…	…

Example usage:

auto filter = LevelFilterPtr::create(QtWarningMsg);
auto formatter = PatternFormatterPtr::create("%{time} %{message}");
auto sink = StdErrSinkPtr::create();

gQtLogger << filter << formatter << sink;

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Handler Interface

All handlers implement the Handler interface:

class Handler
{
public:
    enum class HandlerType { Handler, AttrHandler, Filter, Formatter, Sink, Pipeline };
    
    virtual ~Handler() = default;
    virtual HandlerType type() const;
    virtual bool process(LogMessage &lmsg) = 0;
};

The process() method returns:

• true — Continue to the next handler
• false — Stop processing (message is discarded)

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Namespace

All QtLogger classes are in the QtLogger namespace:

using namespace QtLogger;

// Or use fully qualified names:
QtLogger::Logger *logger = QtLogger::Logger::instance();
QtLogger::PatternFormatterPtr fmt = QtLogger::PatternFormatterPtr::create("...");

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