go调用c代码示例

1. 代码功能:
   

   调用posix的共享内存接口,写入和读取共享内存数据;

2. 代码:

package main
/*
#cgo LDFLAGS: -lrt
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
*/
import "C"
import "unsafe"
import "fmt"
import "os"
func main() {
	name := C.CString("testshm")
	defer C.free(unsafe.Pointer(name))
	fd, err := C.shm_open(name, C.int(C.O_RDWR|C.O_CREAT), 0)
	if err != nil {
		fmt.Println(err.Error())
	}
	fmt.Printf("fd:%d", int(fd))
	ret, err := C.ftruncate(fd, 1024*1024)
	if err != nil || ret != 0 {
		fmt.Println("truncate failed.")
		os.Exit(1)
	}
	strTest := `hello, test write to shared memory`
	content := C.CString(strTest)
	res, err := C.write(fd, unsafe.Pointer(content), C.size_t(len(strTest)))
	if err != nil || res == -1 {
		fmt.Println("write to shared memory failed.")
		os.Exit(1)
	}
	C.lseek(fd, 0, C.SEEK_SET)
	//pRead := make([]byte, 100)
	pRead := C.malloc(100)
	defer C.free(pRead)
	bytesRead, err := C.read(fd, unsafe.Pointer(pRead), 100)
	if err != nil {
		fmt.Println(err.Error())
		os.Exit(1)
	}
	fmt.Printf("bytes read :%d, str are:%s", bytesRead, string(C.GoBytes(pRead, 100)))
	C.getchar()
	C.shm_unlink(name)
}

3. 注意引入的头文件注释行与golang的import代码行直接必须无空行;

本文来自:开源中国博客

感谢作者:shawn chen

查看原文:go调用c代码示例

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