#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

const char *path = "/tmp/socket_test";

void handle_error(char *txt)
{
    perror(txt);
    exit(1);
}

int main()
{
    int fd;
    struct sockaddr_un my_addr, serv_addr;

    memset(&my_addr, 0, sizeof(struct sockaddr_un));
    my_addr.sun_family = AF_UNIX;
    strncpy(my_addr.sun_path, path, sizeof(my_addr.sun_path) - 1);
    memset(&serv_addr, 0, sizeof(struct sockaddr_un));
    serv_addr.sun_family = AF_UNIX;
    strncpy(serv_addr.sun_path, path, sizeof(serv_addr.sun_path) - 1);

    if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
        handle_error("socket");

    if (connect(fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)
        handle_error("connect");

    double d1 = 21.1;
    write(fd, (void *)&d1, sizeof(double));
    printf("%f\n", d1);
    close(fd);

    return 0;
}