1 files changed, 55 insertions, 0 deletions
diff --git a/vendor/rustix/examples/dup2_to_replace_stdio.rs b/vendor/rustix/examples/dup2_to_replace_stdio.rs
new file mode 100644
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+++ b/vendor/rustix/examples/dup2_to_replace_stdio.rs
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+//! This is an example of how to use `dup2` to replace the stdin and stdout
+//! file descriptors.
+
+#[cfg(not(windows))]
+fn main() {
+    use rustix::io::{dup2, pipe};
+    use std::io::{BufRead, BufReader};
+    use std::mem::forget;
+
+    // Create some new file descriptors that we'll use to replace stdio's file
+    // descriptors with.
+    let (reader, writer) = pipe().unwrap();
+
+    // Acquire `OwnedFd` instances for stdin and stdout. These APIs are `unsafe`
+    // because in general, with low-level APIs like this, libraries can't assume
+    // that stdin and stdout will be open or safe to use. It's ok here, because
+    // we're directly inside `main`, so we know that stdin and stdout haven't
+    // been closed and aren't being used for other purposes.
+    let (mut stdin, mut stdout) = unsafe { (rustix::io::take_stdin(), rustix::io::take_stdout()) };
+
+    // Use `dup2` to copy our new file descriptors over the stdio file descriptors.
+    //
+    // These take their second argument as an `&mut OwnedFd` rather than the
+    // usual `impl AsFd` because they conceptually do a `close` on the original
+    // file descriptor, which one shouldn't be able to do with just a
+    // `BorrowedFd`.
+    dup2(&reader, &mut stdin).unwrap();
+    dup2(&writer, &mut stdout).unwrap();
+
+    // Then, forget the stdio `OwnedFd`s, because actually dropping them would
+    // close them. Here, we want stdin and stdout to remain open for the rest
+    // of the program.
+    forget(stdin);
+    forget(stdout);
+
+    // We can also drop the original file descriptors now, since `dup2` creates
+    // new file descriptors with independent lifetimes.
+    drop(reader);
+    drop(writer);
+
+    // Now we can print to "stdout" in the usual way, and it'll go to our pipe.
+    println!("hello, world!");
+
+    // And we can read from stdin, and it'll read from our pipe. It's a little
+    // silly that we connected our stdout to our own stdin, but it's just an
+    // example :-).
+    let mut s = String::new();
+    BufReader::new(std::io::stdin()).read_line(&mut s).unwrap();
+    assert_eq!(s, "hello, world!\n");
+}
+
+#[cfg(windows)]
+fn main() {
+    unimplemented!()
+}