Pseudo-terminal not printing output

Question

So here is my code which is designed to open an additional gnome terminal and print the first 20 Fibonacci numbers in the newly opened terminal console:

#include <stdio.h>
#include "apue.h"

int Fibonacci(unsigned int n);

int main() {
    char cmd[256];
    char str[40][256];
    char *name = tempnam(NULL, NULL);
    char *line = "\n";
    FILE *log;

    mkfifo(name, 0777);
    log = fopen(name, "w+");

    for (unsigned int i = 0; i < 20; i++) {
         sprintf(str[(2 * i)], "%s",line);
         fputs(str[(2 * i)], log);
         sprintf(str[(2 * i) + 1], "%u\n", Fibonacci(i));
         fputs(str[(2 * i) + 1], log);
         fflush(NULL);
    }
    if (fork() == 0) {
        sprintf(cmd, "gnome-terminal -e cat %s", name);
        system(cmd);       
        for (unsigned int j = 0; j < 40 ; j++) {    
            fgets(str[j], sizeof(cmd), log);            
        }
        exit(0);
    } else
    if (fork() < 0) {
        perror("fork () error");    
    }
}

int Fibonacci(unsigned int n) {
    if (n == 0) {
        return 0;
    } else
    if (n == 1) {
        return 1;
    } else
    if (n > 1) {
        return Fibonacci(n - 2) + Fibonacci(n - 1);
    }
}

When I compile it, I get the following warning message:

-*- mode: compilation; default-directory: "/usr/lib/gcc/x86_64-linux-gnu/4.8.4/include/" -*-
Compilation started at Sun Sep  3 15:46:28

gcc  -o FIB0   Fibonacci.c
/tmp/ccobnJV9.o: In function `main':
Fibonacci.c:(.text+0x231f): warning: the use of `tempnam' is dangerous, better use `mkstemp'

Compilation finished at Sun Sep  3 15:46:28

When I execute it from the gnome terminal command line, the new terminal pops open but with no output! How could I fix this code to make it work?

When I use

 sprintf(cmd, "xterm -e cat %s", name);

instead of "gnome-terminal", it works correctly. So how does one communicate between gnome terminals using GCC?

Answer 1

Try

sprintf(cmd, "gnome-terminal -e \"cat %s\"", name);

gnone-terminal's man request a string after -e.