Sets the environment variable
key to the value
value for the currently running
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:
This function may panic if
key is empty, contains an ASCII equals sign
or the NUL character
'\0', or when
value contains the NUL character.
use std::env; let key = "KEY"; env::set_var(key, "VALUE"); assert_eq!(env::var(key), Ok("VALUE".to_string()));