c++怎么使用共享内存_c++共享内存使用方法

#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <iostream>
#include <cstring>
<p>int main() {
const char* name = "/my_shared_memory";
const size_t size = 4096;</p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">// 创建共享内存对象
int fd = shm_open(name, O_CREAT | O_RDWR, 0666);
if (fd == -1) {
    perror("shm_open");
    return 1;
}

// 设置大小
if (ftruncate(fd, size) == -1) {
    perror("ftruncate");
    return 1;
}

// 映射内存
void* ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (ptr == MAP_FAILED) {
    perror("mmap");
    return 1;
}

// 写入数据
const char* msg = "Hello from process!";
std::strcpy((char*)ptr, msg);

std::cout << "Data written to shared memory.\n";

// 解除映射
munmap(ptr, size);
close(fd);
return 0;

#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <iostream>
<p>int main() {
const char* name = "/my_shared_memory";
const size_t size = 4096;</p><pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">// 打开已存在的共享内存
int fd = shm_open(name, O_RDONLY, 0);
if (fd == -1) {
    perror("shm_open read");
    return 1;
}

// 映射内存
void* ptr = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0);
if (ptr == MAP_FAILED) {
    perror("mmap read");
    return 1;
}

// 读取并输出
std::cout << "Read from shared memory: " << (char*)ptr << "\n";

// 清理
munmap(ptr, size);
close(fd);
return 0;

// 在写入进程结束前或单独脚本中调用
shm_unlink("/my_shared_memory");