1  /* Interfaces for obtaining random bytes.
       2     Copyright (C) 2016-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _SYS_RANDOM_H
      20  #define _SYS_RANDOM_H 1
      21  
      22  #include <features.h>
      23  #include <sys/types.h>
      24  
      25  /* Flags for use with getrandom.  */
      26  #define GRND_NONBLOCK 0x01
      27  #define GRND_RANDOM 0x02
      28  #define GRND_INSECURE 0x04
      29  
      30  __BEGIN_DECLS
      31  
      32  /* Write LENGTH bytes of randomness starting at BUFFER.  Return the
      33     number of bytes written, or -1 on error.  */
      34  ssize_t getrandom (void *__buffer, size_t __length,
      35                     unsigned int __flags) __wur
      36                     __attr_access ((__write_only__, 1, 2));
      37  
      38  /* Write LENGTH bytes of randomness starting at BUFFER.  Return 0 on
      39     success or -1 on error.  */
      40  int getentropy (void *__buffer, size_t __length) __wur
      41                  __attr_access ((__write_only__, 1, 2));
      42  
      43  __END_DECLS
      44  
      45  #endif /* _SYS_RANDOM_H */