Add macros to check if logging at a given label is enabled #10768
Conversation
|
I like the idea of having this, but I'm not sure that it's necessary to have a whole array of macros for all the logging levels. I think that it'd be nice to have something like: // src/libstd/logging.rs
pub static DEBUG: u32 = 4;
pub static INFO: u32 = 3;
pub static WARN: u32 = 2;
pub static ERROR: u32 = 1;
// only one macro
macro_rules! log_enabled($lvl:expr) ( ... )I would also rather not special-case the debug log level and instead clearly document that |
| information you would want to log is expensive to produce), you can use the | ||
| following macros: | ||
|
|
||
| * `log_enabled!(level)` - returns true iff logging of the given level is enabled |
There was a problem hiding this comment.
Ah, sorry, I used iff to mean if and only if. Too much academia, API documentation is not the place for this :P
There was a problem hiding this comment.
Oh, I didn't know that!
|
Pushed a new version |
|
|
||
| Note that when logging of level `DEBUG` is disabled at compile time, | ||
| `log_enabled!(DEBUG)` will still return `true`. If you want to make completely | ||
| sure, also test for `cfg!(not(ndebug))`. |
There was a problem hiding this comment.
Hm, sorry about flip-flopping on this issue, but now that I actually read this in words it seems more awful then when I imagined this in my head.
That being said, I like only having one log_enabled! macro, and I think that we can just rely on LLVM optimizations to figure this out. The macro can be defined as:
macro_rules! log_enabled( ($lvl:expr) => (
$lvl <= _log_level() && (log != 4 || cfg(not(ndebug)))
) )Or at least I think I got the boolean logic there right
This is useful when the information that is needed to do useful logging is expensive to produce.
|
And another version :) |
|
Test has been added |
This is useful when the information that is needed to do useful logging is expensive to produce.
[arithmetic_side_effects] Consider referenced allowed or hard-coded types Fix rust-lang#10767 ``` changelog: [`arithmetic_side_effects`]: Do not fire when dealing with allowed or hard-coded types that are referenced. ```
This is useful when the information that is needed to do useful logging
is expensive to produce.