sockets/id_echo_cl.c

/* id_echo_cl.c

   A client for the UDP "echo" service. This program sends each of its
   command-line arguments as a datagram to the server and echoes the
   contents of the datagrams that the server sends in response.

   See also id_echo_sv.c.
*/
#include "id_echo.h"

int
main(int argc, char *argv[])
{
    int sfd, j;
    size_t len;
    ssize_t numRead;
    char buf[BUF_SIZE];

    if (argc < 2 || strcmp(argv[1], "--help") == 0)
        usageErr("%s host msg...\n", argv[0]);

    /* Construct server address from first command-line argument */

    sfd = inetConnect(argv[1], SERVICE, SOCK_DGRAM);
    if (sfd == -1)
        fatal("Could not connect to server socket");

    /* Send remaining command-line arguments to server as separate datagrams */

    for (j = 2; j < argc; j++) {
        len = strlen(argv[j]);
        if (write(sfd, argv[j], len) != len)
            fatal("partial/failed write");

        numRead = read(sfd, buf, BUF_SIZE);
        if (numRead == -1)
            errExit("read");

        printf("[%ld bytes] %.*s\n", (long) numRead, (int) numRead, buf);
    }

    exit(EXIT_SUCCESS);
}