在macOS中更改命名管道缓冲区大小

Question

有没有办法控制通过mkfifo创建的命名管道的缓冲区大小？

我正在使用macOS 10.13.2，缓冲区大小似乎固定为8192字节。我能用这段代码获得这个数字：

#include <iostream>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <thread>

#define BUFFER_SIZE 1024*1024
#define FIFO_PATH "/Users/joao/Desktop/fifo"

void readFifo() {
        auto fd = open(FIFO_PATH, O_RDONLY);

        if (fd < 0) {
                std::cerr << "Failed to open fifo for reading" << std::endl;
                return;
        }

        std::cout << "Ready to read!" << std::endl;

        char buffer[BUFFER_SIZE];
        auto total_bytes_read = 0;

        while (total_bytes_read < BUFFER_SIZE) {
                auto bytes_read = read(fd, buffer, BUFFER_SIZE);
                std::cout << "Read " << bytes_read << " bytes" << std::endl;

                total_bytes_read += bytes_read;
        }

        close(fd);
}

int main(int argc, const char * argv[]) {
        unlink(FIFO_PATH);

        if (mkfifo(FIFO_PATH, 0666) != 0) {
                std::cerr << "Failed to create fifo" << std::endl;
                return 1;
        }

        std::thread reader(readFifo);

        auto fd = open(FIFO_PATH, O_WRONLY);

        if (fd < 0) {
                std::cerr << "Failed to open fifo for writing" << std::endl;
                return 1;
        }

        char buffer[BUFFER_SIZE];

        for (int i = 0; i < BUFFER_SIZE; i++) {
                buffer[i] = 'a';
        }

        auto bytes_written = write(fd, buffer, BUFFER_SIZE);

        reader.join();
        std::cout << "Wrote " << bytes_written << " bytes" << std::endl;

        unlink(FIFO_PATH);
        return 0;
}