Function set_logger

pub fn set_logger(logger: &'static dyn Log) -> Result<(), SetLoggerError>

Sets the global logger to a &'static Log.

This function may only be called once in the lifetime of a program. Any log events that occur before the call to set_logger completes will be ignored.

This function does not typically need to be called manually. Logger implementations should provide an initialization method that installs the logger internally.

Availability

This method is available even when the std feature is disabled. However, it is currently unavailable on thumbv6 targets, which lack support for some atomic operations which are used by this function. Even on those targets, set_logger_racy will be available.

Errors

An error is returned if a logger has already been set.

Examples

use log::{error, info, warn, Record, Level, Metadata, LevelFilter};

static MY_LOGGER: MyLogger = MyLogger;

struct MyLogger;

impl log::Log for MyLogger {
    fn enabled(&self, metadata: &Metadata) -> bool {
        metadata.level() <= Level::Info
    }

    fn log(&self, record: &Record) {
        if self.enabled(record.metadata()) {
            println!("{} - {}", record.level(), record.args());
        }
    }
    fn flush(&self) {}
}

log::set_logger(&MY_LOGGER).unwrap();
log::set_max_level(LevelFilter::Info);

info!("hello log");
warn!("warning");
error!("oops");