Struct duct::Handle [−][src]
pub struct Handle { /* fields omitted */ }Expand description
A handle to a running expression, returned by the
start method.
Calling start followed by
into_output on the handle is
equivalent to run. Note that unlike
std::process::Child,
most of the methods on Handle take &self rather than &mut self, and a
Handle may be shared between multiple threads.
Like std::process::Child, Handle doesn’t do anything special in its
destructor. If you drop a handle without waiting on it, child processes and
background IO threads will keep running, and the children will become
zombie processes when they
exit. That’s a resource leak, similar to leaking memory or file handles.
Note that in contrast to Handle, a
ReaderHandle kills child processes in its
destructor, to avoid creating zombies.
See the shared_child
crate for implementation details behind making handles thread safe.
Implementations
Wait for the running expression to finish, and return a reference to its
std::process::Output.
Multiple threads may wait at the same time.
Errors
In addition to all the IO errors possible with
std::process::Child,
wait will return an
ErrorKind::Other
IO error if child returns a non-zero exit status. To suppress this
error and return an Output even when the exit status is non-zero, use
the unchecked method.
Check whether the running expression is finished. If it is, return a
reference to its
std::process::Output.
If it’s still running, return Ok(None).
Errors
In addition to all the IO errors possible with
std::process::Child,
try_wait will return an
ErrorKind::Other
IO error if child returns a non-zero exit status. To suppress this
error and return an Output even when the exit status is non-zero, use
the unchecked method.
Wait for the running expression to finish, and then return a
std::process::Output
object containing the results, including any captured output. This
consumes the Handle. Calling
start followed by
into_output is equivalent to
run.
Errors
In addition to all the IO errors possible with
std::process::Child,
into_output will return an
ErrorKind::Other
IO error if child returns a non-zero exit status. To suppress this
error and return an Output even when the exit status is non-zero, use
the unchecked method.
Kill the running expression and await all the child processes. Any
errors that would normally result from a non-zero exit status are
ignored, as with
unchecked.
Note that as with
std::process::Child::kill,
this does not kill any grandchild processes that the children have
spawned on their own. It only kills the child processes that Duct
spawned itself. See
gotchas.md
for an extensive discussion of this behavior.