tcp_test.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <fcntl.h>

#define PORT 33000
#define SERVER "aranka-pi"

static void sendStr(int sd, const char *str)
{
    if(write(sd, str, strlen(str)+1) < 0)
    {
        perror("write() failed\n");
    }
}

static void sendChar(int sd, char c)
{
    if(write(sd, &c, 1) < 0)
    {
        perror("write() failed\n");
    }
}

int main()
{
    int sd, rc;
    struct sockaddr_in serveraddr;
    struct hostent *hostp;
    char buff[128]; // read buff

    // Udelani socketu 
    sd = socket(AF_INET, SOCK_STREAM, 0);
    if(sd < 0)
    {
        perror("socket() error\n");
        return 255;
    }

    // vyplneni infa o serveru
    memset(&serveraddr, 0, sizeof(struct sockaddr_in));
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_port = htons(PORT);

    hostp = gethostbyname(SERVER); // resolve jmena serveru
    if(hostp == NULL)
    {
        perror("Failed to resolve "SERVER"\n");
        return 255;
    }
    memcpy(&serveraddr.sin_addr, hostp->h_addr, sizeof(serveraddr.sin_addr));

    // connect na serveraddr
    rc = connect(sd, (struct sockaddr*)&serveraddr, sizeof(serveraddr));
    if(rc < 0)
    {
        perror("Failed to connect()\n");
        return 255;
    }

    // nastaveni nonblocking
    fcntl(sd, F_SETFL, fcntl(sd, F_GETFL, 0) | O_NONBLOCK);

    // zapnout gui
    sendChar(sd, 'h');
    sendChar(sd, 'a');
    sleep(60);
    sendChar(sd, 's');
    while(1)
    {
        while((rc = read(sd, buff, sizeof(buff))) > 0)
        {
            if(strncmp(buff, "bear ", 5) == 0)
            {
                int x, y, w, h;
                if(sscanf(buff, "bear %d %d %d %d\n", &x, &y, &w, &h) == 4)
                    printf("Bear rectangle: [%d; %d] %dx%d\n", x, y, w, h);
            }
        }
        usleep(50000);
    }


    close(sd);
}