如下是源代码实现直接编译即可使用:
//author sam by 20170621
// 使用示例:
// package utils
// import (
// "fmt"
// u "lpaiche.com/utils"
// "testing"
// )
// type MyData struct {
// Col1 int
// Col2 int
// Col3 int
// Col4 int
// }
// //-----------------------------------------test_mmap_shm----------------------------
// func TestWriteMmapShm(t *testing.T) {
// shm := u.NewShmMmap("test")
// fmt.Println(shm)
// fmt.Println("写入共享内存")
// data := (*MyData)(shm.GetWritePointer())
// data.Col1 = 105
// data.Col2 = 276
// data.Col3 = 2021
// data.Col4 = 2020
// fmt.Println(data)
// }
// func TestReadMmapShm(t *testing.T) {
// fmt.Println("读取共享内存")
// shm := u.NewShmMmap("test")
// data1 := (*MyData)(shm.GetReadPointer())
// fmt.Println(data1)
// }
// func TestFreeMmapShm(t *testing.T) {
// fmt.Println("删除共享内存")
// shm := u.NewShmMmap("test")
// shm.Remove()
// }
// //-------------------------------------------test_mem_shm------------------------
// func TestShmmemGetWritePointer(t *testing.T) {
// shm := u.NewShmMem("/tmp/shm")
// fmt.Println(shm)
// data := (*MyData)(shm.GetWritePointer())
// defer shm.Close()
// data.Col1 = 1111
// data.Col2 = 2222
// data.Col3 = 3333
// data.Col4 = 4444
// fmt.Println(data)
// }
// func TestShmmemGetReadPointer(t *testing.T) {
// fmt.Println("读取共享内存")
// shm := u.NewShmMem("/tmp/shm")
// data1 := (*MyData)(shm.GetReadPointer())
// fmt.Println(data1)
// }
// func TestShmmemRemove(t *testing.T) {
// shm := u.NewShmMem("/tmp/shm")
// fmt.Println("删除共享内存")
// shm.Remove()
// }
package utils
/* #cgo linux LDFLAGS: -lrt #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include <sys/types.h> #include <sys/shm.h> #include <sys/ipc.h> //-----------------cgo_mmap---------------------------- #define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) int my_shm_new(char *name) { //shm_unlink(name); return shm_open(name,O_RDWR|O_CREAT|O_EXCL,FILE_MODE); } int my_shm_open(char *name) { return shm_open(name,O_RDWR,FILE_MODE); } void my_shm_free(char *name){ shm_unlink(name); } //------------------cgo_shm------------------------- int my_shmmem_open(char *file,int size,int open_flag){ int shm_id; key_t key; key = ftok(file,0x111); if(key == -1){ return -1; } if(open_flag) shm_id = shmget(key,size,IPC_CREAT|IPC_EXCL|0600); else shm_id = shmget(key,0); if(shm_id == -1){ return -1; } return shm_id; } int my_shmmem_rm(int shm_id){ shmctl(shm_id,IPC_RMID,NULL); return 0; } */
import "C"
import (
"fmt"
"unsafe"
)
//------------------------------mmap实现共享内存操作-------------------------------------------------------------
type ShmMmap struct {
name string
size int
}
func NewShmMmap(shm_name string,shm_size ...int) *ShmMmap {
shm_size1 := 1 * 1000 * 1000 * 1000 //默认共享内存大小1G
if shm_size != nil {
shm_size1 = shm_size[0]
}
shmm := ShmMmap{name: shm_name,size: shm_size1}
return &shmm
}
func (this *ShmMmap) GetWritePointer() unsafe.Pointer {
this.Remove()
fd,err := C.my_shm_new(C.CString(this.name))
if err != nil {
fmt.Println(err)
return nil
}
shm_size := (C.__off_t)(this.size)
C.ftruncate(fd,shm_size)
ptr,err := C.mmap(nil,4*1000*1000*1000,C.PROT_READ|C.PROT_WRITE,C.MAP_SHARED,fd,0)
if err != nil {
fmt.Println(err)
return nil
}
C.close(fd)
return (unsafe.Pointer(ptr))
}
func (this *ShmMmap) Remove() {
C.my_shm_free(C.CString(this.name))
}
func (this *ShmMmap) GetReadPointer() unsafe.Pointer {
fd,err := C.my_shm_open(C.CString(this.name))
if err != nil {
fmt.Println(err)
return nil
}
shm_size := (C.size_t)(this.size)
ptr,shm_size,0)
if err != nil {
fmt.Println(err)
return nil
}
C.close(fd)
return (unsafe.Pointer(ptr))
}
//---------------------------------------shm实现共享内存操作------------------------------------------
type ShmMem struct {
filename string
size int
shmid int
pointer unsafe.Pointer
}
func NewShmMem(pathfilename string,shm_size ...int) *ShmMem {
shm_size1 := 4096 //默认共享内存大小4k
if shm_size != nil {
shm_size1 = shm_size[0]
}
shmm := ShmMem{filename: pathfilename,size: shm_size1,shmid: 0}
return &shmm
}
func (this *ShmMem) initShmit() {
filename := C.CString(this.filename)
defer C.free(unsafe.Pointer(filename))
this.shmid = int(C.my_shmmem_open(filename,C.int(this.size),C.int(1)))
if this.shmid < 0 {
this.shmid = int(C.my_shmmem_open(filename,C.int(0)))
}
if this.shmid < 0 {
fmt.Println("open share memery Failed!")
Panic("open share memery Failed! ")
}
}
func (this *ShmMem) GetWritePointer() unsafe.Pointer {
this.initShmit()
addr := C.shmat(C.int(this.shmid),nil,0)
this.pointer = unsafe.Pointer(addr)
return this.pointer
}
func (this *ShmMem) GetReadPointer() unsafe.Pointer {
return this.GetWritePointer()
}
func (this *ShmMem) Close() {
C.shmdt(this.pointer)
}
func (this *ShmMem) Remove() {
this.initShmit()
C.my_shmmem_rm(C.int(this.shmid))
}
原文链接:https://www.f2er.com/go/188377.html