Auto merge of #24741 - cgwalters:note-setenv-and-unsetenv-are-not-threadsafe, r=alexcrichton

See:
https://sourceware.org/bugzilla/show_bug.cgi?id=4887#c9
https://bugs.freedesktop.org/show_bug.cgi?id=65681

I just noticed this while talking to someone who was using
`os.environ['FOO'] = 'BAR'` in Python and since I'm learning Rust, I
was curious if it did anything special here (and the answer appears to
be no).

Java got this right by disallowing `setenv()` from the start.
This commit is contained in:
bors 2015-05-14 07:15:51 +00:00
commit 0a1a53d693

View File

@ -243,6 +243,17 @@ impl Error for VarError {
/// Sets the environment variable `k` to the value `v` for the currently running
/// process.
///
/// Note that while concurrent access to environment variables is safe in Rust,
/// some platforms only expose inherently unsafe non-threadsafe APIs for
/// inspecting the environment. As a result extra care needs to be taken when
/// auditing calls to unsafe external FFI functions to ensure that any external
/// environment accesses are properly synchronized with accesses in Rust.
///
/// Discussion of this unsafety on Unix may be found in:
///
/// - [Austin Group Bugzilla](http://austingroupbugs.net/view.php?id=188)
/// - [GNU C library Bugzilla](https://sourceware.org/bugzilla/show_bug.cgi?id=15607#c2)
///
/// # Examples
///
/// ```
@ -260,6 +271,17 @@ pub fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(k: K, v: V) {
/// Removes an environment variable from the environment of the currently running process.
///
/// Note that while concurrent access to environment variables is safe in Rust,
/// some platforms only expose inherently unsafe non-threadsafe APIs for
/// inspecting the environment. As a result extra care needs to be taken when
/// auditing calls to unsafe external FFI functions to ensure that any external
/// environment accesses are properly synchronized with accesses in Rust.
///
/// Discussion of this unsafety on Unix may be found in:
///
/// - [Austin Group Bugzilla](http://austingroupbugs.net/view.php?id=188)
/// - [GNU C library Bugzilla](https://sourceware.org/bugzilla/show_bug.cgi?id=15607#c2)
///
/// # Examples
///
/// ```