RE: GCC 4.6.2 C++ thread cancellation issue

[Mike Dalpee <mikedalpee@xxxxxxxxxxxx>]

Oops, missed your first comment - attached are both corrected files.

________________________________________
From: Jonathan Wakely [jwakely.gcc@xxxxxxxxx]
Sent: Friday, May 11, 2012 3:13 PM
To: Mike Dalpee
Cc: Ian Lance Taylor; gcc-help@xxxxxxxxxxx
Subject: Re: GCC 4.6.2 C++ thread cancellation issue

On 11 May 2012 19:41, Mike Dalpee wrote:
> Ok, I have provided the two examples as attachments.  I had to transcribe these from printouts, so I apologize if there are any typos that prevent them from immediately compiling.

Both files need
s/pthread tid;/pthread_t tid;/

For the first program I get no abort:

Thread created
In ThreadRun
In Some3rdPartyFunction
Cancelling Thread
Joining cancelled thread
Rethrowing abi::_forced_unwind
Returning from main

Did you mean to put an empty exception specification on the
Some3rdPartyFunction?

For the second I see an abort

Thread created
In ThreadRun
Handling int exception
In Some3rdPartyFunction
Cancelling Thread
Joining cancelled thread
terminate called after throwing an instance of 'int'
Aborted

> I used the following commands to build these:
>
> gcc -g bug1.cpp -o bug1 -lstdc++ -lpthread
> gcc -g bug2.cpp -o bug2 -lstdc++ -lpthread

It won't change the behaviour, but any reason you don't use these
commands instead?

g++ -g bug1.cpp -o bug1 -pthread
g++ -g bug2.cpp -o bug2 -pthread

i.e. compile with the g++ driver so libstdc++ is linked in
automatically, and use -pthread so _REENTRANT is defined, as well as
linking to libpthread.

#include <cxxabi.h>
#include <pthread.h>
#include <time.h>
#include <iostream>

using namespace std;

// abort does not occur if:
// 1) throw() is removed or
// 2) an exception is specified (i.e., throw(some_exception))

void
Some3rdPartyFunction() throw()
{
	cout << "In Some3rdPartyFunction" << endl;

	struct timespec delay = {5,0};

	int ret =
		nanosleep(
			&delay,
			NULL);

	cout << "Returning from Some3rdPartyFunction" << endl;
}

extern "C" void*
ThreadRun(
	void* argP)
{
	cout << "In ThreadRun" << endl;

	Some3rdPartyFunction();

	cout << "Returning from ThreadRun" << endl;

	return NULL;
}

int
main(
	int   argc,
	char* argv[])
{
	pthread_t tid;

	int ret =
		pthread_create(
			&tid,
			NULL,
			ThreadRun,
			NULL);

	cout << "Thread created" << endl;

	struct timespec delay =  {1,0};

	ret =
		nanosleep(
			&delay,
			NULL);

	cout << "Cancelling Thread" << endl;

	ret =
		pthread_cancel(
			tid);

	void* returnValue = NULL;

	cout << "Joining cancelled thread" << endl;

	ret =
		pthread_join(
			tid,
			&returnValue);

	cout << "Returning from main" << endl;

	return 0;
}

#include <cxxabi.h>
#include <pthread.h>
#include <time.h>
#include <iostream>

using namespace std;

// abort does not occur if the catch/rethrow
// of abi::__forced_unwind is removed

void
Some3rdPartyFunction()
{
	cout << "In Some3rdPartyFunction" << endl;

	try
	{
	
		struct timespec delay = {5,0};

		int ret =
			nanosleep(
				&delay,
				NULL);
	}
	catch (abi::__forced_unwind&)
	{
		cout << "Rethrowing abi::_forced_unwind" << endl;

		throw;
	}

	cout << "Returning from Some3rdPartyFunction" << endl;
}

extern "C" void*
ThreadRun(
	void* argP)
{
	cout << "In ThreadRun" << endl;

	try
	{
		throw 1;
	}
	catch (int&)
	{
		cout << "Handling int exception" << endl;


		Some3rdPartyFunction();
	}

	cout << "Returning from ThreadRun" << endl;

	return NULL;
}

int
main(
	int   argc,
	char* argv[])
{
	pthread_t tid;

	int ret =
		pthread_create(
			&tid,
			NULL,
			ThreadRun,
			NULL);

	cout << "Thread created" << endl;

	struct timespec delay =  {1,0};

	ret =
		nanosleep(
			&delay,
			NULL);

	cout << "Cancelling Thread" << endl;

	ret =
		pthread_cancel(
			tid);

	void* returnValue = NULL;

	cout << "Joining cancelled thread" << endl;

	ret =
		pthread_join(
			tid,
			&returnValue);

	cout << "Returning from main" << endl;

	return 0;
}