log.hpp File Reference

Asynchronous logging (5.10). More...

#include "fastmm/core/config_macros.hpp"
#include "fastmm/core/enums.hpp"
#include "fastmm/core/fixed_point.hpp"
#include "fastmm/core/fixed_string.hpp"
#include "fastmm/core/spsc_ring.hpp"
#include "fastmm/core/strong_id.hpp"
#include "fastmm/core/time.hpp"
#include <fmt/base.h>
#include <atomic>
#include <concepts>
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <string>
#include <string_view>
#include <type_traits>

Go to the source code of this file.

Classes
struct	fastmm::LogDescriptor
struct	fastmm::LogRecord
struct	fastmm::Secret< T >
	Wrap a value to have it rendered as "***". More...
class	fastmm::Logger
	Process-wide registry of per-thread rings + the sink thread. Implemented in log_sink.cpp. More...

Namespaces
namespace	fastmm

Macros
#define	FASTMM_LOG_IMPL(lvl, fmt_str, ...)
	fmt_str must be a string literal.
#define	FASTMM_LOG_TRACE(fmt_str, ...)    FASTMM_LOG_IMPL(::fastmm::LogLevel::Trace, fmt_str __VA_OPT__(, ) __VA_ARGS__)
#define	FASTMM_LOG_DEBUG(fmt_str, ...)    FASTMM_LOG_IMPL(::fastmm::LogLevel::Debug, fmt_str __VA_OPT__(, ) __VA_ARGS__)
#define	FASTMM_LOG_INFO(fmt_str, ...)    FASTMM_LOG_IMPL(::fastmm::LogLevel::Info, fmt_str __VA_OPT__(, ) __VA_ARGS__)
#define	FASTMM_LOG_WARN(fmt_str, ...)    FASTMM_LOG_IMPL(::fastmm::LogLevel::Warn, fmt_str __VA_OPT__(, ) __VA_ARGS__)
#define	FASTMM_LOG_ERROR(fmt_str, ...)    FASTMM_LOG_IMPL(::fastmm::LogLevel::Error, fmt_str __VA_OPT__(, ) __VA_ARGS__)

Typedefs
using	fastmm::LogRing = SpscRing< LogRecord, kLogRingSize >

Enumerations
enum class	fastmm::LogArgType : std::uint8_t {   fastmm::Int = 1 , fastmm::Uint = 2 , fastmm::Double = 3 , fastmm::Bool = 4 ,   fastmm::Char = 5 , fastmm::PriceFx = 6 , fastmm::QtyFx = 7 , fastmm::NotionalFx = 8 ,   fastmm::Str = 9 , fastmm::Secret = 10 }

Functions
template<class T >
Secret< std::decay_t< T > >	fastmm::secret (T &&v)
FASTMM_FORCE_INLINE bool	fastmm::log_enabled (LogLevel lvl) noexcept

Variables
constexpr std::size_t	fastmm::kLogRecordBytes = 256
constexpr std::size_t	fastmm::kLogMaxStrBytes = 64
constexpr std::size_t	fastmm::kLogRingSize = 8192
	records per thread (2 MiB)
constexpr std::size_t	fastmm::kLogMaxThreads = 64
std::atomic< std::uint8_t >	fastmm::g_log_level {static_cast<std::uint8_t>(LogLevel::Info)}
	Global level (runtime); FASTMM_MIN_LOG_LEVEL is the compile-time floor.

Detailed Description

Asynchronous logging (5.10).

FASTMM_LOG_INFO("filled {} \@ {} on {}", qty, px, side);

The call site captures a pointer to a static LogDescriptor (format string, file, line, level) plus the packed argument values into a 256-byte LogRecord in the calling thread's SpscRing. Nothing is formatted on the caller's thread; the LogSink thread pops records, formats them with fmt and writes them to a FILE*. When a ring is full the record is dropped and counted - the hot path never blocks.

The format string is validated at compile time against the argument types (fmt), so a mismatch is a compile error rather than a runtime surprise on the sink thread.

Supported argument types: integers, floating point, bool, char, Price/Qty/Notional (formatted as exact decimals), enums (via to_string() when available, else the underlying integer), string_view / const char* / std::string / FixedString (copied, truncated to kLogMaxStrBytes), Timestamp/Duration (ns as integers), Secret<T> ("***").

Macro Definition Documentation

FASTMM_LOG_IMPL

#define FASTMM_LOG_IMPL	(		lvl,
			fmt_str,
			...
	)

Value:

  do {                                                                                    \
    if constexpr (::fastmm::detail::log_compiled(lvl)) {                                  \
      if (::fastmm::log_enabled(lvl)) {                                                   \
        static constexpr ::fastmm::LogDescriptor fastmm_log_desc_{                        \
            fmt_str, __FILE__, __LINE__, lvl};                                            \
        [&](const auto&... fastmm_a_) {                                                   \
          static_cast<void>(                                                              \
              ::fmt::format_string<::fastmm::detail::LogFmtType<decltype(fastmm_a_)>...>( \
                  fmt_str));                                                              \
          ::fastmm::detail::log_emit(fastmm_log_desc_, fastmm_a_...);                     \
        }(__VA_ARGS__);                                                                   \
      }                                                                                   \
    }                                                                                     \
  } while (0)

fmt_str must be a string literal.

The generic lambda lets us spell the packed argument types for the compile-time format check without touching the arguments' values.

FASTMM_LOG_TRACE

#define FASTMM_LOG_TRACE	(		fmt_str,
			...
	)		FASTMM_LOG_IMPL(::fastmm::LogLevel::Trace, fmt_str __VA_OPT__(, ) __VA_ARGS__)

FASTMM_LOG_DEBUG

#define FASTMM_LOG_DEBUG	(		fmt_str,
			...
	)		FASTMM_LOG_IMPL(::fastmm::LogLevel::Debug, fmt_str __VA_OPT__(, ) __VA_ARGS__)

FASTMM_LOG_INFO

#define FASTMM_LOG_INFO	(		fmt_str,
			...
	)		FASTMM_LOG_IMPL(::fastmm::LogLevel::Info, fmt_str __VA_OPT__(, ) __VA_ARGS__)

FASTMM_LOG_WARN

#define FASTMM_LOG_WARN	(		fmt_str,
			...
	)		FASTMM_LOG_IMPL(::fastmm::LogLevel::Warn, fmt_str __VA_OPT__(, ) __VA_ARGS__)

FASTMM_LOG_ERROR

#define FASTMM_LOG_ERROR	(		fmt_str,
			...
	)		FASTMM_LOG_IMPL(::fastmm::LogLevel::Error, fmt_str __VA_OPT__(, ) __VA_ARGS__)