Hi guys, I have a problem with a little C script who should run as a server and launch a popup for every message arriving.
The execl syntax is correct because if I try a little script with 
main() { execl(...); }
it works.
When I put it in a while(1) cicle it doesn't work. Everything else is working, like printf or string operation, but not the execl. Even if I fork it doesn't work.
I really don't know what I can do ... can anyone help me?
Thanks in advice for your help and sorry for my bad english.
Here's the complete server C code.
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <string.h>
#define BUFLEN 512
#define PORT 9930
void diep(char *s) {
     perror(s);
     exit(1);
}
int main() {
    struct sockaddr_in si_me, si_other;
    int s, i, slen=sizeof(si_other), broadcastPermission;
    char buf[100], zeni[BUFLEN];
    if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1)
       diep("socket");
    broadcastPermission = 1;
    if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, (void *) &broadcastPermission, sizeof(broadcastPermission)) < 0)
        diep("setsockopt() failed");
    memset((char *) &si_me, 0, sizeof(si_me));
    si_me.sin_family = AF_INET;
    si_me.sin_port = htons(PORT);
    si_me.sin_addr.s_addr = htonl(INADDR_ANY);
    if (bind(s, &si_me, sizeof(si_me))==-1)
       diep("bind");
    while (1) {
        if (recvfrom(s, buf, BUFLEN, 0, &si_other, &slen)==-1) diep("recvfrom()");
        //printf("Received packet from %s:%d\nData: %s\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port), buf);
 strcpy(zeni, "");
 strcat(zeni, "zenity --warning --title Hack!! --text ");
 strcat(zeni, buf);
 printf("cmd: %s\n", zeni);
 //system (zeni);
 execl("/usr/bin/zenity", "/usr/bin/zenity", "--warning", "--title", "Warn!", "--text", buf, (char *) NULL);
    }
    close(s);
    return 0;
}