7.4 Command and Event Processing

Example

/*
 * This function blocks until an event message is available
 * and returns the received event to the calling routine.
 *  MUX_HANDLE is typedef'd in adidef.h for portability.
 */
void myWaitForEvent( unsigned drvid, 
                     MUX_HANDLE muxhandle,
                     ADI_EVENT *event )
    {
    ...
    /*
     *  adiFetchAndProcess() assigns a non-zero event id
     *  when an event is generated for the app.
     */
    event->id = 0 ;

    while( event->id == 0 )
        {
#ifdef UNIX
        struct pollfd fds[1];
        fds[0].events = POLLIN;
        fds[0].fd     = muxhandle;

        if (  poll( fds, 1, -1 ) < 0 )
            {
            if ( errno == EINTR )
                continue ;
            perror("poll") ;
            exit( 1 );
            }
#elif defined OS2
        APIRET ret;
        if( ( ret = (int)DosWaitEventSem( muxhandle,
                    (unsigned)SEM_INDEFINITE_WAIT ) ) != 0 )
            {
            printf( "Error on DosWaitEventSem: %d\n", ret );
            exit( 1 );
            }
#elif defined WIN32
        if( WaitForSingleObject( muxhandle, INFINITE ) 
                                        ==WAIT_FAILED )
            {
            printf( "Error on WaitForSingleObject: %d\n",
                     GetLastError() );
            exit( 1 );
            }
#endif

        /* 
         * Allow ADI to fetch the event and process it through its
         * internal state machine.
         */
        adiFetchAndProcess( drvid, event );
        }

    return;
    }

7.4.1 Unix Signals