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学习 C/C++ (Part 24: libuv) #295

Open nonocast opened 2 years ago

nonocast commented 2 years ago

setup

跟着 libuv/build-instructions 指引通过cmake编译和安装:

~ mkdir -p build
~ cd build
~ cmake ..
~ cmake --build build
~ sudo make install

hello world

guide#hello-world uv.c

// clang -arch arm64 -luv uv.c

#include <stdio.h>
#include <stdlib.h>
#include <uv.h>

int main() {
  uv_loop_t *loop = malloc(sizeof(uv_loop_t));
  uv_loop_init(loop);

  printf("Now quitting.\n");
  uv_run(loop, UV_RUN_DEFAULT);

  uv_loop_close(loop);
  free(loop);
  return 0;
}

tcp echo

guide中的代码在src/docs/code下, GitHub: tcp-echo-server/main.c，根据这个操练一遍。

uv.c

// clang -arch arm64 -luv uv.c

#include <stdio.h>
#include <stdlib.h>
#include <uv.h>

#define DEFAULT_PORT 3000
#define DEFAULT_BACKLOG 128

uv_loop_t *loop;
struct sockaddr_in addr;

void on_new_connection(uv_stream_t *server, int status);
void on_close(uv_handle_t *handle);

int main() {
  loop = uv_default_loop();

  uv_tcp_t server;
  uv_tcp_init(loop, &server);

  uv_ip4_addr("0.0.0.0", DEFAULT_PORT, &addr);

  uv_tcp_bind(&server, (const struct sockaddr *) &addr, 0);
  int r = uv_listen((uv_stream_t *) &server, DEFAULT_BACKLOG, on_new_connection);
  if (r) {
    fprintf(stderr, "Listen error %s\n", uv_strerror(r));
    return 1;
  }
  return uv_run(loop, UV_RUN_DEFAULT);
}

void on_new_connection(uv_stream_t *server, int status) {
  if (status < 0) {
    fprintf(stderr, "New connection error %s\n", uv_strerror(status));
    // error!
    return;
  }

  uv_tcp_t *client = (uv_tcp_t *) malloc(sizeof(uv_tcp_t));
  uv_tcp_init(loop, client);
  if (uv_accept(server, (uv_stream_t *) client) == 0) {
    printf("new connection.\n");
    // uv_read_start((uv_stream_t *) client, alloc_buffer, echo_read);
  } else {
    uv_close((uv_handle_t *) client, on_close);
  }
}

void on_close(uv_handle_t *handle) {
  free(handle);
}

通过nc localhost 3000可以看到new connection输出，这里必须在on_new_connection中调用uv_accept否则不能响应第二次接入请求，你可以理解uv_accept重新投递listen请求，这个和IOCP的概念是一致的。

完整的代码直接看github就好，很容易理解。

小结:

参考资料