Module std::env

The program's arguments and environment variables, read from the root's Env into Buf<u8>s (hence with Env, Alloc). They are bytes, as passed: an argument need not be UTF-8, and its as_bytes() is a path as it is. The environment is a snapshot taken at process start. In the simulated world (the library default, the playground) there are no arguments and no variables; a test installs its own Env handler with the ones it wants.

Source: std/env.weir; committed interface: std/env.iface. Index

• fn arg: The ith argument after the program's name (0 is the first), None past the last.
• fn args_len: How many arguments follow the program's name.
• fn var: The value of the environment variable name, None when it is unset or name is not a variable's name (empty, or holding = or a NUL byte).

fn arg

pub fn arg(i: usize) -> Option<Buf<u8>> with Env, Alloc

The ith argument after the program's name (0 is the first), None past the last.

Committed interface (std/env.iface):

bound Env: Env any
bound Alloc: Alloc any
aborts: Alloc.alloc
scheduling point: Env not quiet

fn args_len

pub fn args_len() -> usize with Env

How many arguments follow the program's name.

Committed interface (std/env.iface):

bound Env: Env any
may diverge
scheduling point: Env not quiet

fn var

pub fn var(name: &[u8]) -> Option<Buf<u8>> with Env, Alloc

The value of the environment variable name, None when it is unset or name is not a variable's name (empty, or holding = or a NUL byte).

Committed interface (std/env.iface):

bound Env: Env any
bound Alloc: Alloc any
aborts: Alloc.alloc
scheduling point: Env not quiet