Macro log_error 

macro_rules! log_error {
    () => { ... };
    ($($t:tt)*) => { ... };
}

Creates a closure that error logs a formatted string and returns the closure’s argument.

The argument for the error_map! macro must be a format string and some parameters (according to the format_args macro). The macro will then create a closure that just returns its argument, but as a side effect will error log the string which was generated from the macro arguments, appended with error.to_string().

The intended use for log_error! is as a closure argument for the Result::map_err method, error logging a message as a side effect.

Examples

use dsh_api::log_error;

fn save(path: PathBuf, data: &[u8]) -> Result<(), std::io::Error> {
  write(&path, data)
    .map_err(log_error!("writing {} failed, caused by ", path.display()))?;
  Ok(())
}