Simple socket client written in C

client.c

#include <sys/socket.h>
#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <stdarg.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <netdb.h>

#define SERVER_PORT 80
#define MAXLINE 4096

void err_n_die(const char *fmt, ...) {
    int errno_save;
    va_list ap;

    errno_save = errno;

    va_start(ap, fmt);
    vfprintf(stdout, fmt, ap);
    fprintf(stdout, "\n");
    fflush(stdout);

    if(errno_save != 0) {
        fprintf(stdout, "(errno = %d) : %s\n", errno_save, strerror(errno_save));
        fprintf(stdout, "\n");
        fflush(stdout);
    }
    va_end(ap);
    
    exit(1);
}

int main(int argc, char *argv[]) {

    int sockfd, n;
    int sendbytes;
    struct sockaddr_in servaddr;
    char sendline[MAXLINE];
    char recvline[MAXLINE];

    if(argc != 2) 
        err_n_die("usage: %s <server address>", argv[0]);

    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)        
        err_n_die("Error while creating the socket!");
 
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(SERVER_PORT);

    if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
        err_n_die("inet_pton error for %s ", argv[1]);

    if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0) 
        err_n_die("connect failed!");

    sprintf(sendline, "GET / HTTP/1.1\r\n\r\n");
    sendbytes = strlen(sendline);

    if(write(sockfd, sendline, sendbytes) != sendbytes)
        err_n_die("write error");

    memset(recvline, 0, MAXLINE);

    while((n = read(sockfd, recvline, MAXLINE-1)) > 0) {
        printf("%s", recvline);
    }
    if(n < 0)
        err_n_die("read error");

    return EXIT_SUCCESS;
}