extended_sink.hpp File Reference

"Advanced" log sinks that see extended_log_msg metadata and can report being full, plus a fixed-capacity fan-out sink that applies back-pressure across several of them. More...

#include "../microfmt.hpp"
#include "extended_msg.hpp"
#include "sink.hpp"
#include "sync.hpp"
#include <atomic>
#include <concepts>
#include <cstddef>
#include <cstdint>
#include <type_traits>

Include dependency graph for extended_sink.hpp:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Classes
class	microfmt::log::extended_log_sink
	Type-erased handle to an advanced log sink backend, with a severity threshold. Same two-word-plus-vtable shape as log_sink. More...
struct	microfmt::log::extended_log_sink::vtable
struct	microfmt::log::fanout_log_sink_tag< MaxSinks, Channel >
class	microfmt::log::fanout_log_sink< MaxSinks, Channel >
	Fixed-capacity sink that forwards each record to up to MaxSinks advanced sinks ("pins"), applies back-pressure when one is full, and keeps thread-context writers in FIFO order. Nothing here busy-waits. More...
struct	microfmt::log::extended_log_sink_traits< fanout_log_sink_tag< MaxSinks, Channel > >

Namespaces
namespace	microfmt
namespace	microfmt::log
namespace	microfmt::log::detail
	Fixed-capacity logger that formats records before dispatching to sinks.

Concepts
concept	microfmt::log::detail::has_extended_full
concept	microfmt::log::detail::has_extended_flush

Detailed Description

"Advanced" log sinks that see extended_log_msg metadata and can report being full, plus a fixed-capacity fan-out sink that applies back-pressure across several of them.

These sinks intentionally do not mirror the legacy log_sink API: their log takes an extended_log_msg and they may expose full.

// A backend: tag + traits. `context_type` holds the state.
struct my_ring_tag {};
struct my_ring { / * ring buffer, its own lock, ... * / };
 
template <> struct microfmt::log::extended_log_sink_traits<my_ring_tag> {
  using context_type = my_ring;
 
  // Mandatory. msg.meta.can_wait() == false (IRQ): overwrite the oldest
  // data when full. == true (thread): the fan-out already waited for
  // space, so just append, and drop only if that raced.
  static void log(microfmt::value_ref<my_ring> ctx, const microfmt::log::extended_log_msg &msg) noexcept;
 
  // Optional. true when `msg` would not fit without waiting/overwriting.
  static bool full(microfmt::value_ref<my_ring> ctx, const microfmt::log::extended_log_msg &msg) noexcept;
 
  // Optional.
  static void flush(microfmt::value_ref<my_ring> ctx) noexcept;
};