macro_rules! eprintln { () => { ... }; ($($arg:tt)*) => { ... }; }
Expand description
Prints to stderr
, with a newline.
Equivalent to the println!
macro, except that output goes to
stderr
instead of stdout
. See println!
for
example usage.
Use eprintln!
only for error and progress messages. Use println!
instead for the primary output of your program.
NOTE: Not all eprintln!
calls will be captured in tests like std::eprintln!
- Capturing will automatically be activated in test binaries
- Otherwise, only when the
test
feature is enabled
§Panics
Panics if writing to stderr
fails for any reason except broken pipe.
Writing to non-blocking stdout can cause an error, which will lead this macro to panic.
§Examples
use anstream::eprintln;
eprintln!("Error: Could not complete task");