//ww:run-exit 51
// Migrated from 778_bufio_vstream_run row branched_bufio_wrap.
package main;
import os;
import bufio;
import memio;
import io;
export fn main() i32 = {
    let raA: [4]u8;
    raA[0] = 10u8; raA[1] = 11u8; raA[2] = 12u8; raA[3] = 13u8;
    let raB: [4]u8;
    raB[0] = 20u8; raB[1] = 21u8; raB[2] = 22u8; raB[3] = 23u8;
    let mstA: memio.stream = memio.fixed(raA[0:4]);
    let mstB: memio.stream = memio.fixed(raB[0:4]);
    let sel: i32 = 1;
    let src: io.stream = &mstA.vt;
    if (sel == 0) { src = &mstB.vt; };
    let rbuf: [4]u8;
    let wbuf: [4]u8;
    let bc: bufio.stream = bufio.init(src, rbuf[0:4], wbuf[0:4]);
    let vs: io.stream = &bc.vt;
    let out: [4]u8;
    let rd = io.read(vs, out[0:4]);
    let n: size = 0;
    if (rd is size) { n = rd as size; };
    if (n != 4: size) { return 91; };
    if (out[0] != 10u8 || out[3] != 13u8) { return 92; };
    return 51;
};