std::runtime::fs

Source: std/runtime/fs.slk

This is the exact canonical documentation page for std::runtime::fs.

Role#

std::runtime::fs is an implementation-facing runtime module in the shipped std/** tree. It exists so higher-level stdlib surfaces can delegate platform or runtime-specific behavior without changing their public module names.

Canonical Context#

Use the following owning docs for the substantive API/design context for this module:

• runtime
• fs

Notes#

• The shipped source for this module is std/runtime/fs.slk.
• The canonical module name is std::runtime::fs.
• This module now carries the implementation-facing raw metadata surface used by std::fs::Stats (StatInfo, StatResult, stat, lstat, fstat), plus fstat_size for allocation-free descriptor size probes.
• It also carries the borrowed directory-entry bridge used by std::fs::Dir.next_view() (DirEntryBorrowed, DirEntryBorrowedResult, readdir_borrowed, and readdir_borrowed_into).
• The hosted implementation exposes raw chmod and advisory flock/unlock operations for the typed std::fs wrappers. Unsupported runtimes return the stable filesystem Unsupported code rather than exposing a platform errno.
• The wrapper's internal errno mapping is defined for every compilation target. macOS selects its platform values where they differ; WASI stubs use the Linux-shaped ENOTSUP value they store in their runtime errno cell, so merely importing the portable filesystem graph never depends on a hosted-only declaration.
• This page is intentionally implementation-oriented. Downstream users should usually start with the higher-level std module docs listed above unless they are working on the runtime layer itself.