std

std
- __restricted_std_workaround
- alloc
  - __default_lib_allocator
- arch
- ascii
- autodiff
- backtrace
  - helper
- backtrace_rs
  - backtrace
    - libunwind
      - uw
  - print
  - symbolize
    - gimli
      - elf
      - libs_dl_iterate_phdr
      - lru
      - mmap
      - mystd
      - parse_running_mmaps
      - stash
  - types
- bstr
- collections
  - hash
    - map
    - set
  - hash_map
  - hash_set
- env
  - consts
- error
- f128
- f16
- f32
- f64
- ffi
  - c_str
  - os_str
- from
- fs
- hash
  - random
- io
  - error
  - pipe
  - prelude
  - stdio
- macros
- net
  - hostname
  - ip_addr
  - socket_addr
  - tcp
  - udp
- num
- offload
- os
  - darwin
    - fs
    - objc
    - raw
  - fd
    - net
    - owned
    - raw
    - stdio
  - linux
    - fs
    - net
    - process
    - raw
      - arch
  - net
    - linux_ext
      - addr
      - socket
      - tcp
  - raw
  - unix
    - ffi
      - os_str
    - fs
    - io
    - net
      - addr
      - ancillary
      - datagram
      - listener
      - stream
      - ucred
        impl_linux
    - prelude
    - process
    - raw
    - thread
    - xdg
  - wasi
    - ffi
      - os_str
    - fs
    - io
    - prelude
  - wasip2
  - windows
    - ffi
    - fs
    - io
      - handle
      - raw
      - socket
    - net
      - addr
      - listener
      - stream
    - prelude
    - process
    - raw
    - thread
- panic
- panicking
  - panic_count
- pat
- path
- prelude
  - rust_2015
  - rust_2018
  - rust_2021
  - rust_2024
  - rust_future
  - v1
    - ambiguous_macros_only
      - panic
      - vec
- process
- random
- rt
- simd
- std_float
- sync
  - barrier
  - lazy_lock
  - mpmc
    - array
    - context
    - counter
    - error
    - list
    - select
    - utils
    - waker
    - zero
  - mpsc
  - nonpoison
    - condvar
    - mutex
    - rwlock
  - once
  - once_lock
  - oneshot
  - poison
    - condvar
    - mutex
    - rwlock
  - reentrant_lock
- sys
  - alloc
    - unix
      - runtime_symbols
  - args
    - common
    - unix
      - imp
  - backtrace
  - cmath
  - configure_builtins
  - env
    - common
    - unix
  - env_consts
    - os
  - exit
    - runtime_symbols
  - fd
    - unix
  - fs
    - common
    - unix
  - helpers
    - small_c_string
    - wstr
  - io
  - net
    - connection
      - socket
        unix
    - hostname
      - unix
  - os_str
    - bytes
  - pal
    - unix
      - conf
      - stack_overflow
        imp
        
        thread_info
      - time
      - weak
        dlsym
        
        syscall
        
        weak_linkage
  - path
    - unix
  - paths
    - unix
  - personality
    - dwarf
      - eh
    - gcc
  - pipe
    - unix
  - platform_version
  - process
    - env
    - unix
  - random
    - linux
  - stdio
    - unix
  - sync
    - condvar
      - futex
    - futex
      - unix
    - mutex
      - futex
    - once
      - futex
    - once_box
    - rwlock
      - futex
    - thread_parking
      - futex
  - thread
    - unix
      - cgroups
    - unsupported
  - thread_local
    - destructors
      - linux_like
      - list
    - guard
      - key
    - key
      - racy
      - unix
    - native
      - eager
      - lazy
  - time
    - unix
- task
- thread
  - builder
  - current
    - id
  - functions
  - id
  - join_handle
  - lifecycle
  - local
  - local_impl
  - main_thread
  - scoped
  - spawnhook
  - thread
    - thread_name_string
- time
- view

std :: sys :: cmath :: acos

Function `acos`

pub extern "C" fn acos(n: f64) -> f64