Mapping an array to a file via Mmap in Go

别等时光非礼了梦想. 提交于 2019-12-02 17:10:57

For example, revising your sample program,

package main

import (
    "fmt"
    "os"
    "syscall"
    "unsafe"
)

func main() {
    const n = 1e3
    t := int(unsafe.Sizeof(0)) * n

    map_file, err := os.Create("/tmp/test.dat")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    _, err = map_file.Seek(int64(t-1), 0)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    _, err = map_file.Write([]byte(" "))
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    mmap, err := syscall.Mmap(int(map_file.Fd()), 0, int(t), syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    map_array := (*[n]int)(unsafe.Pointer(&mmap[0]))

    for i := 0; i < n; i++ {
        map_array[i] = i * i
    }

    fmt.Println(*map_array)

    err = syscall.Munmap(mmap)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    err = map_file.Close()
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
}
标签
易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!