How can client exit while using fork in jsonrpc-c server

Question

I am using jsonrpc-c to write a remote shell toy.

The client side uses nc to send request to server:

echo "{\"method\":\"sayHello\"}" | nc localhost 1234

The code of the server is simple:

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <signal.h> 
#include "jsonrpc-c.h"
#define DEFAULT_PORT            1234  //the port users will be connecting to

static struct jrpc_server my_server;


cJSON * hello(jrpc_context * ctx, cJSON * params, cJSON *id) {
  pid_t pid = fork();
  if (pid==0)
  {
    freopen( "/dev/null", "w", stdout );
    freopen( "/dev/null", "r", stdin ); 
    signal(SIGCHLD,SIG_IGN);
    while(true){
    printf("hello in child\n");
    }
    exit(1);
  }
  printf("hello in father\n");
    return cJSON_CreateString("done");
}

void main(int argc, char **argv)
{
    int port;
    if (argc == 2) 
        port = atoi(argv[1]);
    else 
        port = DEFAULT_PORT;

    jrpc_server_init(&my_server, (int)port);

    jrpc_register_procedure(&my_server, hello, "sayHello", NULL);

    jrpc_server_run(&my_server);
    jrpc_server_destroy(&my_server);
}

When executing echo "{\"method\":\"sayHello\"}" | nc localhost 1234, the client blocks forever. Are there any methods to let the client exit when the server's parent process returns, while allowing the server's child process to continue running?