Function nstd_env_var 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn nstd_env_var(
    key: &NSTDStr,
) -> NSTDIOStringResult<'_>

Available on crate feature env only.

Retrieves a variable from the process environment.

Parameters:

• const NSTDStr *key - The variable’s key.

Returns

NSTDIOStringResult var - The value of the environment variable, or the I/O operation error code on failure. This will return as NSTD_IO_ERROR_NOT_FOUND if they variable cannot be found, and NSTD_IO_ERROR_INVALID_DATA if the variable isn’t valid Unicode.

Safety

The user of this function must ensure that key is valid for reads.