Class LogSink (2.30.0)

A sink to receive log records.

Constructors

LogSink()

Functions

empty() const

Return true if this object has no backends.

We want to avoid synchronization overhead when checking if a log message is enabled. Most of the time, most messages will be disabled, so incurring the locking overhead on each message would be too expensive and would discourage developers from creating logs. Furthermore, missing a few messages while the change of state "propagates" to other threads does not affect the correctness of the program.

Note that memory_order_relaxed does not provide a compiler barrier either, so in theory stores into the atomic could be reordered by the optimizer. We have no reason to worry about that because all the writes are done inside a critical section protected by a mutex. The compiler cannot (or should not) reorder operations around those.

Returns
Type Description
bool

is_enabled(Severity) const

Return true if severity is enabled.

We want to avoid synchronization overhead when checking if a log message is enabled. Most of the time, most messages will be disabled, so incurring the locking overhead on each message would be too expensive and would discourage developers from creating logs. Furthermore, missing a few messages while the change of state "propagates" to other threads does not affect the correctness of the program.

Note that memory_order_relaxed does not provide a compiler barrier either, so in theory stores into the atomic could be reordered by the optimizer. We have no reason to worry about that because all the writes are done inside a critical section protected by a mutex. The compiler cannot (or should not) reorder operations around those.

Parameter
Name Description
severity Severity
Returns
Type Description
bool

set_minimum_severity(Severity)

Parameter
Name Description
minimum Severity
Returns
Type Description
void

minimum_severity() const

Returns
Type Description
Severity

AddBackend(std::shared_ptr< LogBackend >)

Parameter
Name Description
backend std::shared_ptr< LogBackend >
Returns
Type Description
BackendId

RemoveBackend(BackendId)

Parameter
Name Description
id BackendId
Returns
Type Description
void

ClearBackends()

Returns
Type Description
void

BackendCount() const

Returns
Type Description
std::size_t

Log(LogRecord)

Parameter
Name Description
log_record LogRecord
Returns
Type Description
void

Flush()

Flush all the current backends.

Returns
Type Description
void

static CompileTimeEnabled(Severity)

Return true if the severity is enabled at compile time.

Parameter
Name Description
level Severity
Returns
Type Description
bool constexpr

static Instance()

Return the singleton instance for this application.

Returns
Type Description
LogSink &

static EnableStdClog(Severity)

Enable std::clog on LogSink::Instance().

This is also enabled if the "GOOGLE_CLOUD_CPP_ENABLE_CLOG" environment variable is set.

Parameter
Name Description
min_severity Severity
Returns
Type Description
void

static DisableStdClog()

Disable std::clog on LogSink::Instance().

Note that this will remove the default logging backend.

Returns
Type Description
void

Type Aliases

BackendId

Alias Of: long