# 1.0.0[−][src]Function std::env::set_var

    pub fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(k: K, v: V)

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
- GNU C library Bugzilla

# Panics

This function may panic if `key` is empty, contains an ASCII equals sign `'='` or the NUL character `'\0'`, or when the value contains the NUL character.

# Examples

    use std::env;

    let key = "KEY";
    env::set_var(key, "VALUE");
    assert_eq!(env::var(key), Ok("VALUE".to_string()));Run

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)