The C and C++ Include Header Files

/usr/include/linux/random.h


$ cat -n /usr/include/linux/random.h

     1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
     2	/*
     3	 * include/linux/random.h
     4	 *
     5	 * Include file for the random number generator.
     6	 */
     7	
     8	#ifndef _LINUX_RANDOM_H
     9	#define _LINUX_RANDOM_H
    10	
    11	#include <linux/types.h>
    12	#include <linux/ioctl.h>
    13	#include <linux/irqnr.h>
    14	
    15	/* ioctl()'s for the random number generator */
    16	
    17	/* Get the entropy count. */
    18	#define RNDGETENTCNT	_IOR( 'R', 0x00, int )
    19	
    20	/* Add to (or subtract from) the entropy count.  (Superuser only.) */
    21	#define RNDADDTOENTCNT	_IOW( 'R', 0x01, int )
    22	
    23	/* Get the contents of the entropy pool.  (Superuser only.) */
    24	#define RNDGETPOOL	_IOR( 'R', 0x02, int [2] )
    25	
    26	/* 
    27	 * Write bytes into the entropy pool and add to the entropy count.
    28	 * (Superuser only.)
    29	 */
    30	#define RNDADDENTROPY	_IOW( 'R', 0x03, int [2] )
    31	
    32	/* Clear entropy count to 0.  (Superuser only.) */
    33	#define RNDZAPENTCNT	_IO( 'R', 0x04 )
    34	
    35	/* Clear the entropy pool and associated counters.  (Superuser only.) */
    36	#define RNDCLEARPOOL	_IO( 'R', 0x06 )
    37	
    38	/* Reseed CRNG.  (Superuser only.) */
    39	#define RNDRESEEDCRNG	_IO( 'R', 0x07 )
    40	
    41	struct rand_pool_info {
    42		int	entropy_count;
    43		int	buf_size;
    44		__u32	buf[];
    45	};
    46	
    47	/*
    48	 * Flags for getrandom(2)
    49	 *
    50	 * GRND_NONBLOCK	Don't block and return EAGAIN instead
    51	 * GRND_RANDOM		No effect
    52	 * GRND_INSECURE	Return non-cryptographic random bytes
    53	 */
    54	#define GRND_NONBLOCK	0x0001
    55	#define GRND_RANDOM	0x0002
    56	#define GRND_INSECURE	0x0004
    57	
    58	#endif /* _LINUX_RANDOM_H */