api::debug::log

Logging macros and severity levels.

Macros

Macro	Level	Gate
log_error!	Error	flint-log
log_warn!	Warn	flint-log
log_info!	Info	flint-log
log_debug!	Debug	flint-log
log_trace!	Trace	flint-log

Every level is gated on flint-log, which debug-level-1 and above turn on. At debug-level-0 there is no logging at all, errors included. The table used to say the first three were “Always”; they never were, and a user turning logging down for size was losing the error path without being told.

The gate lives in one place, [__flint_log]. It must not be written into the macro bodies: a cfg inside macro_rules! is resolved against the crate expanding the macro, not this one, and no application declares a flint-log feature. log_debug! and log_trace! carried exactly that cfg and so expanded to nothing in every application, whatever DEBUG= was set to.

Example

log_info!("boot complete in {} ms", 42);

Enums

Level

enum Level {
    Error,
    Warn,
    Info,
    Debug,
    Trace,
}

Log severity level.

Implements: Clone, Copy, Debug, Eq, PartialEq, StructuralPartialEq

Functions

__flint_log

fn __flint_log(_level: Level, _args: core::fmt::Arguments<'_>)

The kernel-provided log write function.

References: Level