Struct SubshFdFrame 

pub struct SubshFdFrame { /* private fields */ }

The descriptors a bare exec redirection moved inside an in-process subshell, each with a copy of what it was before, and the ones the body opened for itself ({var}, sysopen -u, zsystem flock -f).

!!! WARNING: RUST-ONLY TYPE — C forks and needs none of this !!! exec 3>file / exec 3>&- with no command is permanent — c:4035 “specifically don’t restore the original fd’s” — but inside $( … ) or ( … ) it is permanent only for the forked child (Src/exec.c:4816, c:2880), whose fd table dies with it. zshrs runs the body in process, so the parent’s descriptors are saved here the first time the body’s permanent redirection touches each one, and put back when the frame is dropped; a descriptor from 10 up that the body allocated is closed, as the child’s exit would ((exec {v}>f); exec {w}>g gives w 11 in zsh). A body that redirects nothing permanently costs nothing.

Implementations

impl SubshFdFrame

pub fn enter() -> Self

Open a frame for a subshell body.

pub fn touch(fd: i32)

Called before a permanent redirection changes fd: keep a copy (past the script’s {var} range — see lowfd::movefd_past_script) unless the innermost frame already has one. Outside any frame the redirection really is permanent and nothing is kept.

pub fn opened(fd: i32)

Called when the body takes a descriptor from 10 up for the script (fdtable_set to a user kind): it did not exist for the parent, so the frame closes it on the way out.

Trait Implementations

impl Drop for SubshFdFrame

fn drop(&mut self)

Put the parent’s descriptors back, most recent first.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.