stdlib/sys/random.h

   1 /* Interfaces for obtaining random bytes.
   2    Copyright (C) 2016-2022 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 */