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| -rw-r--r-- | src/libcore/macros.rs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs index 0032bedc7ed..a0c87f13e5d 100644 --- a/src/libcore/macros.rs +++ b/src/libcore/macros.rs @@ -349,6 +349,26 @@ macro_rules! try { /// write!(&mut v, "s = {:?}", s).unwrap(); // uses io::Write::write_fmt /// assert_eq!(v, b"s = \"abc 123\""); /// ``` +/// +/// Note: This macro can be used in `no_std` setups as well +/// In a `no_std` setup you are responsible for the +/// implementation details of the components. +/// +/// ```no_run +/// # extern crate core; +/// use core::fmt::Write; +/// +/// struct Example; +/// +/// impl Write for Example { +/// fn write_str(&mut self, _s: &str) -> core::fmt::Result { +/// unimplemented!(); +/// } +/// } +/// +/// let mut m = Example{}; +/// write!(&mut m, "Hello World").expect("Not written"); +/// ``` #[macro_export] #[stable(feature = "rust1", since = "1.0.0")] macro_rules! write { |