exception thrown on cancelation when using ctrl+c - casablanca

Question

pplx::task<void> RestInterface::Getsxxxx()
{
utility::stringstream_t ss;
pplx::cancellation_token_source cts;
pplx::cancellation_token ct = cts.get_token();
ss<<"http://"<<URL<<":"<<PORT<<PATH<<ZALL;
http_client client(U(ss.str()));
///here were using the jSON function for URI to request the REST API
///else the name of the API can be passed to stream also.
http_request requestJson(methods::GET);
requestJson.headers().set_content_type(U("application/json"));
///you must perform the request
///against a server that provides JSON data.
return client.request(requestJson, ct).then([=](http_response response) -> pplx::task<web::json::value>
{
///If the status is OK extract the body of the response into a JSON value
if(!getCancelledSate())
{
if (response.status_code() == status_codes::OK)
{
return response.extract_json();
}
else
{
// return an empty JSON value
isConnected = false;
return pplx::task_from_result(web::json::value());
}
}
else
{
//try{
cts.cancel();
//}
//catch(http_exception const & e)
//{
// std::cout<<__FILE__<<"["<<__LINE__<<"]"<<"Exception:"<< e.what() << std::endl;
//}
}
}, ct).then([=](pplx::task<web::json::value> previousTask)
{
try{
std::cout <<" before previousTask.wait()"<< std::endl;
///Get the JSON value from the task and call the traversal method
if(previousTask.wait() == pplx::task_status::canceled){
//Do nothing
std::cout <<" after previousTask.wait()"<< std::endl;
}else{
web::json::value const & dataValue = previousTask.get();
m_dataJson = dataValue;
///clear string streambuffer
m_Buffer.str("");
m_Buffer.clear();
m_Buffer << m_dataJson.serialize();
utility::string_t streamJson = m_Buffer.str();
if((strxxxxcmp(streamJson, APP_ACTIVE) < 0)){
isConnected = false;
//......So work
}else{
//......So work
}
}
}
catch(http_exception const & e)
{
isConnected = false;
std::cout<<__FILE__<<"["<<__LINE__<<"]"<<"Exception:"<< e.what() << std::endl;
}
});
}
void RestInterface::xxxxz()
{
try
{
isConnected = true;
Getsxxxx().wait();
}
catch(const std::exception &e)
{
std::cout<<__FILE__<<"["<<__LINE__<<"]"<<"Exception:"<< e.what() << std::endl;
//printf("Error exception:%s\n", e.what());
}
}
Now i have a problem. we have a scenario where we have to cancel the Task when a signal is generated like for e.g. when SIGINT is generated...
when user gives SIGINT using Ctrl+C Sometimes i can see the below message.
**/build/casablanca-FHxOgj/casablanca-2.8.0/Release/include/pplx/pplxtasks.h:1835: pplx::task_status pplx::details::_Task_impl_base::_Wait(): Assertion `_IsCompleted()' failed.
Aborted**
i think that some task is throwing an exception that is not handled, but i am not entirely sure which one and about the reason. Can anybody share some thoughts on it.
any help will be great