Function solana_rbpf::helpers::rand

pub fn rand(
    min: u64, 
    max: u64, 
    unused3: u64, 
    unused4: u64, 
    unused5: u64, 
    _context: &mut HelperContext, 
    _ro_regions: &[MemoryRegion], 
    _rw_regions: &[MemoryRegion]
) -> Result<u64, Error>

Returns a random u64 value comprised between min and max values (inclusive). Arguments 3 to 5 are unused.

Relies on rand() function from libc, so libc::srand() should be called once before this helper is used.

Examples

extern crate libc;
extern crate solana_rbpf;
extern crate time;

use solana_rbpf::helpers;
use solana_rbpf::memory_region::MemoryRegion;

unsafe {
    libc::srand(time::precise_time_ns() as u32)
}

let regions = [MemoryRegion::default()];
let n = helpers::rand(3, 6, 0, 0, 0, &mut None, &regions, &regions).unwrap();
assert!(3 <= n && n <= 6);