diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs index 03f5f838311a9..23b826291ffd4 100644 --- a/library/std/src/io/mod.rs +++ b/library/std/src/io/mod.rs @@ -917,6 +917,19 @@ pub trait Read { /// # } /// ``` /// + /// # Usage Notes + /// + /// `read_to_end` attempts to read a source until EOF, but many sources are continuous streams + /// that do not send EOF. In these cases, `read_to_end` will block indefinitely. Standard input + /// is one such stream which may be finite if piped, but is typically continuous. For example, + /// `cat file | my-rust-program` will correctly terminate with an `EOF` upon closure of cat. + /// Reading user input or running programs that remain open indefinitely will never terminate + /// the stream with `EOF` (e.g. `yes | my-rust-program`). + /// + /// Using `.lines()` with a [`BufReader`] or using [`read`] can provide a better solution + /// + ///[`read`]: Read::read + /// /// [`Vec::try_reserve`]: crate::vec::Vec::try_reserve #[stable(feature = "rust1", since = "1.0.0")] fn read_to_end(&mut self, buf: &mut Vec) -> Result { @@ -960,6 +973,19 @@ pub trait Read { /// (See also the [`std::fs::read_to_string`] convenience function for /// reading from a file.) /// + /// # Usage Notes + /// + /// `read_to_string` attempts to read a source until EOF, but many sources are continuous streams + /// that do not send EOF. In these cases, `read_to_string` will block indefinitely. Standard input + /// is one such stream which may be finite if piped, but is typically continuous. For example, + /// `cat file | my-rust-program` will correctly terminate with an `EOF` upon closure of cat. + /// Reading user input or running programs that remain open indefinitely will never terminate + /// the stream with `EOF` (e.g. `yes | my-rust-program`). + /// + /// Using `.lines()` with a [`BufReader`] or using [`read`] can provide a better solution + /// + ///[`read`]: Read::read + /// /// [`std::fs::read_to_string`]: crate::fs::read_to_string #[stable(feature = "rust1", since = "1.0.0")] fn read_to_string(&mut self, buf: &mut String) -> Result { @@ -1262,6 +1288,20 @@ pub trait Read { /// Ok(()) /// } /// ``` +/// +/// # Usage Notes +/// +/// `read_to_string` attempts to read a source until EOF, but many sources are continuous streams +/// that do not send EOF. In these cases, `read_to_string` will block indefinitely. Standard input +/// is one such stream which may be finite if piped, but is typically continuous. For example, +/// `cat file | my-rust-program` will correctly terminate with an `EOF` upon closure of cat. +/// Reading user input or running programs that remain open indefinitely will never terminate +/// the stream with `EOF` (e.g. `yes | my-rust-program`). +/// +/// Using `.lines()` with a [`BufReader`] or using [`read`] can provide a better solution +/// +///[`read`]: Read::read +/// #[stable(feature = "io_read_to_string", since = "1.65.0")] pub fn read_to_string(mut reader: R) -> Result { let mut buf = String::new();