diff options
| -rw-r--r-- | library/std/src/process.rs | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/library/std/src/process.rs b/library/std/src/process.rs index 15ac9e402c5..f9cfd11e906 100644 --- a/library/std/src/process.rs +++ b/library/std/src/process.rs @@ -71,11 +71,15 @@ //! .spawn() //! .expect("failed to execute child"); //! -//! { -//! // limited borrow of stdin -//! let stdin = child.stdin.as_mut().expect("failed to get stdin"); +//! // If the child process fills its stdout buffer, it may end up +//! // waiting until the parent reads the stdout, and not be able to +//! // read stdin in the meantime, causing a deadlock. +//! // Writing from another thread ensures that stdout is being read +//! // at the same time, avoiding the problem. +//! let mut stdin = child.stdin.take().expect("failed to get stdin"); +//! std::thread::spawn(move || { //! stdin.write_all(b"test").expect("failed to write to stdin"); -//! } +//! }); //! //! let output = child //! .wait_with_output() @@ -1145,14 +1149,21 @@ impl Stdio { /// .spawn() /// .expect("Failed to spawn child process"); /// - /// { - /// let stdin = child.stdin.as_mut().expect("Failed to open stdin"); + /// let mut stdin = child.stdin.take().expect("Failed to open stdin"); + /// std::thread::spawn(move || { /// stdin.write_all("Hello, world!".as_bytes()).expect("Failed to write to stdin"); - /// } + /// }); /// /// let output = child.wait_with_output().expect("Failed to read stdout"); /// assert_eq!(String::from_utf8_lossy(&output.stdout), "!dlrow ,olleH"); /// ``` + /// + /// Writing more than a pipe buffer's worth of input to stdin without also reading + /// stdout and stderr at the same time may cause a deadlock. + /// This is an issue when running any program that doesn't guarantee that it reads + /// its entire stdin before writing more than a pipe buffer's worth of output. + /// The size of a pipe buffer varies on different targets. + /// #[stable(feature = "process", since = "1.0.0")] pub fn piped() -> Stdio { Stdio(imp::Stdio::MakePipe) |