进程间通信设施 —— IPC

目录

• 1 命名管道
  • 1.1 同步阻塞
  • 1.2 异步非阻塞
• 2 消息队列（仅 Linux 可用）
• 3 共享内存
  • 3.1 基础共享内存设施

作者

赵曦

日期

2025/09/25

版本

1.0

上一篇教程：基于异步 I/O 的协程设施
下一篇教程：串口通信模块

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1 命名管道

相关类：

• 同步： rm::PipeServer, rm::PipeClient
• 异步： rm::async::PipeServer, rm::async::PipeClient

管道是一种半双工的通信方式，允许一个进程与另一个进程进行通信。命名管道（Named Pipe）是一种特殊类型的管道，它具有名称，可以在不同的进程之间进行通信。

RMVL 提供了跨平台的命名管道实现，并提供了协程支持，Windows 下基于 Windows 命名管道，Linux 下基于 Unix FIFO 实现。

1.1 同步阻塞

服务端

• C++

  #include <rmvl/io/ipc.hpp>
   
  using namespace rm;
   
  int main() {
      PipeServer server("mypipe");
   
      bool success = server.write("message");
      if (!success) {
          printf("Write failed\n");
          return -1;
      }
   
      std::string msg = server.read();
      if (msg.empty()) {
          printf("Read failed\n");
          return -1;
      }
   
      printf("Received: %s\n", msg.c_str());
  }

• Python

  import rm
   
  server = rm.PipeServer("mypipe")
   
  success = server.write("message")
  if not success:
      print("Write failed")
      return -1
   
  msg = server.read()
  if not msg:
      print("Read failed")
      return -1
   
  print(f"Received: {msg}")

客户端

• C++

  #include <rmvl/io/ipc.hpp>
   
  using namespace rm;
   
  int main() {
      PipeClient client("mypipe");
   
      std::string msg = client.read();
      if (msg.empty()) {
          printf("Read failed\n");
          return -1;
      }
      printf("Received: %s\n", msg.c_str());
   
      bool success = client.write("received: " + msg);
      if (!success) {
          printf("Write failed\n");
          return -1;
      }
  }

• Python

  import rm
   
  client = rm.PipeClient("mypipe")
   
  msg = client.read()
  if not msg:
      print("Read failed")
      return -1
  print(f"Received: {msg}")
   
  success = client.write("received: " + msg)
  if not success:
      print("Write failed")
      return -1

1.2 异步非阻塞

服务端

#include <rmvl/io/ipc.hpp>
 
using namespace rm;
 
async::Task<> session(async::PipeServer server) {
    bool success = co_await server.write("message");
    if (!success) {
        printf("Write failed\n");
        co_return;
    }
 
    std::string msg = co_await server.read();
    if (msg.empty()) {
        printf("Read failed\n");
        co_return;
    }
 
    printf("Received: %s\n", msg.c_str());
}
 
int main() {
    async::IOContext io_context{};
    async::PipeServer server("mypipe");
 
    co_spawn(io_context, session, std::move(server));
    
    // 此处可以使用 co_spawn 注册其他 I/O 任务
 
    io_context.run();
    return 0;
}

客户端

#include <rmvl/io/ipc.hpp>
 
using namespace rm;
 
async::Task<> session(async::PipeClient client) {
    std::string msg = co_await client.read();
    if (msg.empty()) {
        printf("Read failed\n");
        co_return;
    }
    printf("Received: %s\n", msg.c_str());
 
    bool success = co_await client.write("received: " + msg);
    if (!success) {
        printf("Write failed\n");
        co_return;
    }
}
 
int main() {
    async::IOContext io_context{};
    async::PipeClient client("mypipe");
 
    co_spawn(io_context, session, std::move(client));
 
    // 此处可以使用 co_spawn 注册其他 I/O 任务
 
    io_context.run();
    return 0;
}

2 消息队列（仅 Linux 可用）

相关类： rm::MqServer 及 rm::MqClient

服务端

#include <rmvl/io/ipc.hpp>
 
using namespace rm;
 
int main() {
    MqServer server("/myqueue");
 
    bool success = server.send("message");
    if (!success) {
        printf("Send failed\n");
        return -1;
    }
 
    std::string msg = server.receive();
    if (msg.empty()) {
        printf("Receive failed\n");
        return -1;
    }
 
    printf("Received: %s\n", msg.c_str());
}

客户端

#include <rmvl/io/ipc.hpp>
 
using namespace rm;
 
int main() {
    MqClient client("/myqueue");
 
    std::string msg = client.receive();
    if (msg.empty()) {
        printf("Receive failed\n");
        return -1;
    }
 
    printf("Received: %s\n", msg.c_str());
 
    bool success = client.send("received: " + msg);
    if (!success) {
        printf("Send failed\n");
        return -1;
    }
}

3 共享内存

相关类： rm::SHMBase 以及 rm::RingBufferSlotSHM

共享内存（Shared Memory）是一种极其高效的进程间通信方式，允许多个进程访问同一块内存区域，RMVL 提供了跨平台的共享内存实现。

3.1 基础共享内存设施

#include <rmvl/io/ipc.hpp>
 
using namespace rm;
 
int main() {
    // 创建或打开共享内存
    SHMBase shm("/myshm", 1024);
 
    // 写入数据
    const char data[] = "Hello, Shared Memory!";
    shm.write(0, data, strlen(data) + 1);
 
    // 读取数据
    char buffer[64]{};
    shm.read(0, buffer, sizeof(buffer));
    printf("Read from SHM: %s\n", buffer);
 
    return 0;
}