sendto generates SIGSEGV

Hi,

I've written an c++ class which wrappes a socket.. With function writen() you can write to an TCP and UDP socket ( TCP : pointer to stuct sockaddr == NULL; UDP : pointer to struct sockaddr != NULL). If I use this function with TCP sockets all works. If I call this function for an UDP socket it generates an SIGSEGV signal.
What is wrong?

with regards,
Oliver

ssize_t writen( const void * vptr, size_t n, struct sockaddr * to)

{
        size_t          nleft = n;
        ssize_t         nwritten;
        const char      *ptr = static_cast< const char * >( vptr);
        
        struct sigaction new_sa;
        struct sigaction old_sa;
        
        new_sa.sa_handler = SIG_IGN;
        ::sigemptyset( & new_sa.sa_mask);
        new_sa.sa_flags = 0;
        ::sigaction( SIGPIPE, & new_sa, & old_sa);              

        while ( nleft > 0)
        {

                if ( ( nwritten = ::sendto( m_handle, ptr, nleft, 0, to, 

sizeof * to)

)<=0)

                {
                        if ( errno == EINTR)
                                nwritten = 0;   // and call sendto() again
                        else if ( errno == EPIPE)
                        {
                                ::sigaction( SIGPIPE, & old_sa, 0);

                                return -1;              // write to sock with 

no readers (peer has the sock closed)

                        }
                        else
                        {
                                ::sigaction( SIGPIPE, & old_sa, 0);
                                throw; // error
                        }
                }

                nleft -= nwritten;
                ptr   += nwritten;
        }
        ::sigaction( SIGPIPE, & old_sa, 0);     // set to its previous action

        return n;
}

here the output of the generated core file:

Core was generated by 'lt-ogx 192.168.1.3 10000'. Program terminated with signal 11, Segmentation fault. rw_common (): write: Success.
warning: unable to get global thread event mask [New Thread 1024 (LWP 32350)]
rw_common (): write: Success.
warning: stop_or_attach_thread: generic error #0 0x0 in ?? ()

Two hours ago you asked this very same question at the linux-net -list. At how many lists you are asking this ?

You are presenting incomplete source, and worse, incomplete
debug trace. Furthermore, this really does not look like KERNEL
problem, which makes it Out-of-Topic issue at these lists.

From certain signature features in the very scant debug data, I would venture to think that you are running it at Solaris, and debugging it there.

Do yourself a favour and learn to use debuggers, and compile for
debugging. ``Backtrace'' or ``where'' (or whatever the debugger
of your choice calls it) is your friend in most cases.

Syscall trace may give you also some clues in some cases. At Solaris see: 'man truss'. At Linux see: 'man strace'.

If you can show strace output with SIGSEGV during a network syscall,
now THAT would be most appropriate at the linux-net list.

/Matti Aarnio