unix_sigpipe
The tracking issue for this feature is: #97889
The #[unix_sigpipe = "..."] attribute on fn main() can be used to specify how libstd shall setup SIGPIPE on Unix platforms before invoking fn main(). This attribute is ignored on non-Unix targets. There are three variants:
#[unix_sigpipe = "inherit"]#[unix_sigpipe = "sig_dfl"]#[unix_sigpipe = "sig_ign"]
#[unix_sigpipe = "inherit"]
Leave SIGPIPE untouched before entering fn main(). Unless the parent process has changed the default SIGPIPE handler from SIG_DFL to something else, this will behave the same as #[unix_sigpipe = "sig_dfl"].
#[unix_sigpipe = "sig_dfl"]
Set the SIGPIPE handler to SIG_DFL. This will result in your program getting killed if it tries to write to a closed pipe. This is normally what you want if your program produces textual output.
Example
#![feature(unix_sigpipe)] #[unix_sigpipe = "sig_dfl"] fn main() { loop { println!("hello world"); } }
% ./main | head -n 1
hello world
#[unix_sigpipe = "sig_ign"]
Set the SIGPIPE handler to SIG_IGN before invoking fn main(). This will result in ErrorKind::BrokenPipe errors if you program tries to write to a closed pipe. This is normally what you want if you for example write socket servers, socket clients, or pipe peers.
This is what libstd has done by default since 2014. (However, see the note on child processes below.)
Example
#![feature(unix_sigpipe)] #[unix_sigpipe = "sig_ign"] fn main() { loop { println!("hello world"); } }
% ./main | head -n 1
hello world
thread 'main' panicked at 'failed printing to stdout: Broken pipe (os error 32)', library/std/src/io/stdio.rs:1016:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Note on child processes
When spawning child processes, the legacy Rust behavior if #[unix_sigpipe] is not specified is to
reset SIGPIPE to SIG_DFL.
If #[unix_sigpipe = "..."] is specified, no matter what its value is, the signal disposition of
SIGPIPE is no longer reset. This means that the child inherits the parent's SIGPIPE behavior.