* `log!(level, ...)` - the generic logging macro, takes a level as a u32 and any
related `format!` arguments
-* `debug!(...)` - a macro hard-wired to the log level of 4
-* `info!(...)` - a macro hard-wired to the log level of 3
-* `warn!(...)` - a macro hard-wired to the log level of 2
-* `error!(...)` - a macro hard-wired to the log level of 1
+* `debug!(...)` - a macro hard-wired to the log level of `DEBUG`
+* `info!(...)` - a macro hard-wired to the log level of `INFO`
+* `warn!(...)` - a macro hard-wired to the log level of `WARN`
+* `error!(...)` - a macro hard-wired to the log level of `ERROR`
All of these macros use the same style of syntax as the `format!` syntax
extension. Details about the syntax can be found in the documentation of
-`std::fmt` along with the Rust tutorial/manual
+`std::fmt` along with the Rust tutorial/manual.
+
+If you want to check at runtime if a given logging level is enabled (e.g. if the
+information you would want to log is expensive to produce), you can use the
+following macro:
+
+* `log_enabled!(level)` - returns true if logging of the given level is enabled
## Enabling logging
use rt::logging::{Logger, StdErrLogger};
use rt::task::Task;
+/// Debug log level
+pub static DEBUG: u32 = 4;
+/// Info log level
+pub static INFO: u32 = 3;
+/// Warn log level
+pub static WARN: u32 = 2;
+/// Error log level
+pub static ERROR: u32 = 1;
+
/// This function is called directly by the compiler when using the logging
/// macros. This function does not take into account whether the log level
/// specified is active or not, it will always log something if this method is
--- /dev/null
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// xfail-fast
+// exec-env:RUST_LOG=logging-enabled=info
+
+use std::logging;
+
+fn main() {
+ if log_enabled!(logging::DEBUG) {
+ fail!("what?! debugging?");
+ }
+ if !log_enabled!(logging::INFO) {
+ fail!("what?! no info?");
+ }
+}