android + pthread + c++ = SIGSEGV

The following code compiles and runs on standard linux:

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

using namespace std;

class Foo
{
    public:
        Foo();
        void go_thread();
        void stop_thread();
    private:
        static void* worker( void* param );
        pthread_t m_pt;
};

Foo::Foo()
{
    m_pt = 0;
}

void Foo::go_thread()
{
    int success = pthread_create( &m_pt, NULL, worker, static_cast<void*>(this) );

    if( success == 0 )
    {
        cout << "thread started" << endl;
    }
}

void Foo::stop_thread()
{
    int success = pthread_joi开发者_开发技巧n( m_pt, NULL );

    if( success == 0 )
    {
        cout << "thread stopped" << endl;
    }
}

void* Foo::worker( void* p )
{
    cout << "thread running" << endl;
    return 0;
}

int main()
{
    Foo f;
    f.go_thread();
    f.stop_thread();
    return 0;
}

and produces the following output:

$ ./a.out
thread started
thread running
thread stopped
$

This code also builds with the Android NDK (r5b). However, when I adb push the resulting executable to a device and run it, I get a SIGSEGV before main() even runs. I've isolated the issue down to pthread_create() It seems the mere existence of this call in my code, never mind execution, causes my prog to seg fault. Any ideas?

It may not be this but try making the function called by pthread create a normal c-function (i.e. declare it as extern "C") not a static member function:

This is because technically the calling convention for static members may be different from the C calling convention that is used by the C-library pthread (though a lot of the times they are the same (which is why it works on your linux box) in my opinion it is not worth the porting risk).

extern "C" void* start_the_thread(void*);

void* start_the_thread(void* data)
{
    Foo*  theObject = static_cast<Foo*>(data);
    // In Java if your Foo had been derived from Runable
    // This is s where theObject->run() would have been called.
    return Foo::worker(data);
}

int success = pthread_create( &m_pt, NULL, start_the_thread, static_cast<void*>(this)

The issue seems to be combining iostream with pthread. I went through and replaced all couts with printf()s, removed the using clause, and removed the iostream header. The code compiled and ran with no issue on the device. I wonder if this is something Google should be made aware of?

The final (working) code looks like:

#include <pthread.h>
#include <stdio.h>

class Foo
{
    public:
        Foo();
        void go_thread();
        void stop_thread();
    private:
        static void* worker( void* param );
        pthread_t m_pt;
};

Foo::Foo()
{
    m_pt = 0;
}

void Foo::go_thread()
{
    int success = pthread_create( &m_pt, NULL, worker, static_cast<void*>(this) );

    if( success == 0 )
    {
        printf( "thread started\n" );
    }
}

void Foo::stop_thread()
{
    int success = pthread_join( m_pt, NULL );

    if( success == 0 )
    {
        printf( "thread stopped\n" );
    }
}

void* Foo::worker( void* p )
{
    printf( "thread running\n" );
    return 0;
}

int main()
{
    Foo f;
    f.go_thread();
    f.stop_thread();
    return 0;
}