The Storyboard IO plugin provides the capability to set application variable values using the Storyboard IO API, allowing external client programs to change data dynamically.

Clients can use the gre_io_add_mdata() function to serialize each variable value that is to be set. As values are added to the serialized buffer, it will be grown until it reaches a maximum size for the transport, at which point the gre_io_add_mdata() function will return -1 indicating it is full. The data can be then sent by using the gre_io_send_mdata() function which will send the change request to the Storyboard IO plugin and set the appropriate values in the Storyboard application.

	Note
	Data must be sent in order of descending alignment requirements. Example: 4u1 4u1 2u1 1s0 is good, 2u1 4u1 4u1 1s0 is not

gre_io_t                    *send_handle;
gre_io_serialized_data_t    *md_buffer = NULL;
uint32_t                    x;
char                        *ptr;
int                         ret;

/*
 * Connect to the application channel
 */
send_handle = gre_io_open("my_channel", GRE_IO_TYPE_WRONLY);
if(send_handle == NULL) {
    printf("Can't open send handle [%s]\n", argv[1]);
    return 0;
}

/*
 * Add some values to be set in the data manager
 */
ptr = "my string";
ret = gre_io_add_mdata(&md_buffer,
  "Test.String",
  "1s0",
  ptr, strlen(ptr)+1);

x = 1;
ret = gre_io_add_mdata(&md_buffer,
  "Test.Number",
  "4u1",
  &x, sizeof(uint32_t));

/*
 * Send the data to be set in the application.
 */
gre_io_send_mdata(send_handle, md_buffer);