Macro warn 

macro_rules! warn {
    ($($input:tt)+) => { ... };
}

Logs a message at the warn level.

Named optional parameters

Named optional parameters are parameters for logging macros to configure this log record.

Each parameter is optional and no order is required. It can appear at the beginning or end of a log macro argument list, but cannot appear among the formatting arguments.

Name	Type / Basic Syntax	Description
logger	Arc<Logger> or Logger	If specified, the given logger will be used instead of the global default logger.
kv	{ key = value }	Key-value pairs for structured logs. See documentation of module kv for more.

Examples

use spdlog::warn;

let warn_description = "Invalid Input";

// Using the global default logger
warn!("warning! {}!", warn_description);

// Or using the specified logger, and structured logging
warn!(logger: input_events, "app received warning", kv: { reason = warn_description });