github.com/ccccaoqing/test@v0.0.0-20220510085219-3985d23445c0/src/crypto/rand/rand.go (about)

     1  // Copyright 2010 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package rand implements a cryptographically secure
     6  // pseudorandom number generator.
     7  package rand
     8  
     9  import "io"
    10  
    11  // Reader is a global, shared instance of a cryptographically
    12  // strong pseudo-random generator.
    13  // On Unix-like systems, Reader reads from /dev/urandom.
    14  // On Windows systems, Reader uses the CryptGenRandom API.
    15  var Reader io.Reader
    16  
    17  // Read is a helper function that calls Reader.Read using io.ReadFull.
    18  // On return, n == len(b) if and only if err == nil.
    19  func Read(b []byte) (n int, err error) {
    20  	return io.ReadFull(Reader, b)
    21  }