variables.c

gchar *_string_get_next_variable(gchar *string, gchar *variable, const size_t variable_size)
{
  gchar *end = NULL;
  gchar *start = g_strstr_len(string, -1, "$(");
  if(start)
  {
    end = g_strstr_len(start, -1, ")");
    if(end)
    {
      *end = '\0';
      g_strlcpy(variable, start, variable_size);
      // the string in variable is null terminated
      end++;
    }
  }

  return end;
}