Question

为后代发布我的作品。在完成我在C ++中的最后一个例子之后实现了我实际上需要在C中一直这样做（真棒，对吧？）。这两次迭代都让我作为一名Java程序员付出了相当大的努力，我认为很多示例代码都留下了太多的漏洞 - 尤其是，当涉及到构建时，从命令行来说相当困难曾经习惯使用Eclipse的人来构建项目并处理依赖项。

如何使用brew安装OSX的依赖项：

brew install flatcc
brew install zeromq

您还需要安装所有标准构建器二进制文件。我使用gcc编译：

gcc publisher.c -o bin/zmq_pub -lzmq -lflatcc
gcc subscriber.c -o bin/zmq_sub -lzmq

这假设您已经安装了zmq和flatcc库，这些库应该在brew完成安装后符号链接到/ usr / local / include。像这样：

zmq_cpub $ls -la /usr/local/include lrwxr-xr-x 1 user group 37 Oct 18 18:43 flatcc -> ../Cellar/flatcc/0.3.4/include/flatcc

您将收到编译错误，例如： Undefined symbols for architecture x86_64:如果您没有正确安装/链接库。编译器/链接器将重命名函数并用_作为前缀，并可能混淆你的地狱。就像Undefined symbols for architecture x86_64 _flatcc_builder_init一样，即使永远不应该是_flatcc_builder_init。

这是因为C / C ++中的链接库与Java中的库根本不同。您也可以安装外部C / C ++库的已知位置，而不是添加JAR的特定项目构建路径。 /usr/local/include，/usr/local/lib，/usr/lib和/usr/include。

在将flatcc二进制文件安装到您的路径后，不要忘记生成要在本地项目中使用的头文件：

flatcc -a Car.fbs

这应该是我在C车道上行驶时遇到的每一个障碍。希望它可以帮助那里的人。

Answer 1

Car.fbs

namespace Test;

table Car {
    name: string;
    model: string;
    year: int;
}
root_type Car;

Subscriber.c（侦听传入的结构）

//  Hello World client
#include "flatbuffers/Car_builder.h" // Generated by `flatcc`.
#include "flatbuffers/flatbuffers_common_builder.h"
#include <zmq.h>

#undef ns
#define ns(x) FLATBUFFERS_WRAP_NAMESPACE(Test, x) // Specified in the schema

struct Car {
    char* name;
    char* model;
    int year;
};

int main (void)
{
    printf ("Connecting to car world server...\n");
    void *context = zmq_ctx_new ();
    void *requester = zmq_socket (context, ZMQ_REQ);
    zmq_connect (requester, "tcp://localhost:5555");

    int request_nbr;
    for (request_nbr = 0; request_nbr != 10; request_nbr++) {
        char buffer [1024];
        printf ("Sending ready signal %d...\n", request_nbr);
        zmq_send (requester, "Hello", 5, 0);
        zmq_recv (requester, buffer, 1024, 0);
        printf ("Received car %d\n", request_nbr);
        ns(Car_table_t) car = ns(Car_as_root(buffer));
        int year = ns(Car_year(car));
        flatbuffers_string_t model = ns(Car_model(car));
        flatbuffers_string_t name = ns(Car_name(car));

        struct Car nextCar;
        // no need to double up on memory!!
        // strcpy(nextCar.model, model);
        // strcpy(nextCar.name, name);
        nextCar.model = model;
        nextCar.name = name;
        nextCar.year = year;

        printf("Year: %d\n", nextCar.year);
        printf("Name: %s\n", nextCar.name);
        printf("Model: %s\n", nextCar.model);
    }
    zmq_close (requester);
    zmq_ctx_destroy (context);
    return 0;
}

Publisher.c（通过zmq套接字发送结构）：

//  Hello World server

#include "flatbuffers/Car_builder.h" // Generated by `flatcc`.
#include "flatbuffers/flatbuffers_common_builder.h"
#include <zmq.h>
#include <unistd.h>
#include <time.h>

#undef ns
#define ns(x) FLATBUFFERS_WRAP_NAMESPACE(Test, x) // specified in the schema

struct Car {
    char name[10];
    char model[10];
    int year;
};

struct Car getRandomCar() {
    struct Car randomCar;
    int a = rand();
    if ((a % 2) == 0) {
        strcpy(randomCar.name, "Ford");
        strcpy(randomCar.model, "Focus");
    } else {
        strcpy(randomCar.name, "Dodge");
        strcpy(randomCar.model, "Charger");
    }
    randomCar.year = rand();
    return randomCar;
}

int main (void)
{
    srand(time(NULL));

    //  Socket to talk to clients
    void *context = zmq_ctx_new ();
    void *responder = zmq_socket (context, ZMQ_REP);
    int rc = zmq_bind (responder, "tcp://*:5555");
    assert (rc == 0);
    int counter = 0;

    while (1) {
        struct Car c = getRandomCar();

        flatcc_builder_t builder, *B;
        B = &builder;
        // Initialize the builder object.
        flatcc_builder_init(B);
        uint8_t *buf; // raw buffer used by flatbuffer
        size_t size; // the size of the flatbuffer
        // Convert the char arrays to strings
        flatbuffers_string_ref_t name = flatbuffers_string_create_str(B, c.name);
        flatbuffers_string_ref_t model = flatbuffers_string_create_str(B, c.model);

        ns(Car_start_as_root(B));
        ns(Car_name_add(B, name));
        ns(Car_model_add(B, model));
        ns(Car_year_add(B, c.year));
        ns(Car_end_as_root(B));
        buf = flatcc_builder_finalize_buffer(B, &size);

        char receiveBuffer [10];
        zmq_recv (responder, receiveBuffer, 10, 0);
        printf ("Received ready signal. Sending car %d.\n", counter);
        sleep (1);          //  Do some 'work'
        zmq_send (responder, buf, size, 0);
        counter++;

        free(buf);
    }
    return 0;
}

ZeroMQ上的简单Flatbuffers C示例 - 通过zmq将struct复制到flatbuffer并再次返回到struct

1 个答案: