Module spdlog::sink

Provides sinks to flexibly output log messages to specified targets.

Sink

Sinks are the objects that actually write logs to their targets. Each sink should be responsible for only single target (e.g file, console, database), and each sink has its own private instance of Formatter object.

A sink has its own level filter that is not shared with the logger, and a Logger can combine multiple Sinks.

Combined sink

A combined sink is also a sink, but instead of having its own target and formatter, it combines other sinks (as sub-sinks).

Operations on a combined sink will be forwarded to its sub-sinks according to the implementation.

Asynchronous combined sink

Asynchronous combined sink is a type of combined sink. Expensive operations (such as log and flush) on asynchronous sinks will be performed asynchronously on other threads.

Since there is no waiting, errors that occur while performing asynchronous operations will not be returned to the upper level, and instead the error handler of the sink will be called.

Users should only use asynchronous combined sinks to wrap actual sinks that require a long time for operations (e.g. involving UDP sends), otherwise they will not get a performance boost or even worse.

Since the thread pool has a capacity limit, the queue may be full in some cases. When users encounter this situation, they have the following options:

• Adjust to a larger capacity via ThreadPoolBuilder::capacity.

• Adjust the overflow policy via AsyncPoolSinkBuilder::overflow_policy.

• Set up an error handler on asynchronous combined sinks via AsyncPoolSinkBuilder::error_handler. The handler will be called when a record is dropped or an operation has failed.

Structs

• AsyncPoolSinkmulti-thread
  A combined sink, logging and flushing asynchronously (thread-pool-based).
• AsyncPoolSinkBuildermulti-thread
  The builder of AsyncPoolSink.
• FileSink
  A sink with a file as the target.
• FileSinkBuilder
  The builder of FileSink.
• JournaldSinkLinux and native and libsystemd
  A sink with systemd-journal as the target.
• JournaldSinkBuilderLinux and native and libsystemd
  The builder of JournaldSink.
• RotatingFileSink
  A sink with a collection of files as the target, rotating according to the rotation policy.
• RotatingFileSinkBuilder
  The builder of RotatingFileSink.
• StdStreamSink
  A sink with a std stream as the target.
• StdStreamSinkBuilder
  The builder of StdStreamSink.
• WinDebugSinkWindows and native
  A sink with a win32 API OutputDebugStringW as the target.
• WinDebugSinkBuilderWindows and native
  The builder of WinDebugSink.
• WriteSink
  A sink that writes log messages into an arbitrary impl Write object.
• WriteSinkBuilder
  The builder of WriteSink.

Enums

• OverflowPolicymulti-thread
  Overflow policy for asynchronous sinks.
• RotationPolicy
  Rotation policies for RotatingFileSink.
• StdStream
  An enum representing the available standard streams.

Traits

• Sink
  A trait for sinks.

Type Aliases

• Sinks
  A container for Sinks.