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Full Discussion: C++ Code to Access Linux Hard Disk Sectors (with a LoopBack Virtual Hard Disk)
Operating Systems Linux C++ Code to Access Linux Hard Disk Sectors (with a LoopBack Virtual Hard Disk) Post 302491389 by Corona688 on Thursday 27th of January 2011 09:43:40 AM
Old 01-27-2011
Why are you opening and closing the file every time you do something?

This especially becomes useless:
Code:
/**
Seek out a Particular Block In the Disk
Block_SIZE=512bytes
*/
int seekDisk()
{
    cout<<"Seeking the File Disk..."<<endl;
    int fd=open(DISK_NAME, O_RDWR);
	if(lseek(fd, 0L, SEEK_SET) != 0L)
        {
                perror("Couldn't seek");
                close(fd);
                return(1);
        }
    close(fd);
    return 0;
}

...because the seek position gets reset every time you open it anyway. You should open it once and keep using the number it gives you. Your read code would end up looking like int readFromDisk(int fd, char *buffer,int length) { ... } iow exactly like normal read...so you might as well get used to ordinary read call instead.

You should also be doing something more with the number of bytes written and read than just printing it. read() and write() will occasionally surprise you with less than you asked for.
 

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LEARN ABOUT DEBIAN

gstreamer::event::seek

GStreamer::Event::Seek(3pm)				User Contributed Perl Documentation			       GStreamer::Event::Seek(3pm)

NAME

       GStreamer::Event::Seek -  Structure describing events that are passed up and down a pipeline

METHODS

   GstEvent = GStreamer::Event::Seek->new ($rate, $format, $flags, $cur_type, $cur, $stop_type, $stop)
       o   $rate (double)

       o   $format (GStreamer::Format)

       o   $flags (GStreamer::SeekFlags)

       o   $cur_type (GStreamer::SeekType)

       o   $cur (64 bit integer)

       o   $stop_type (GStreamer::SeekType)

       o   $stop (64 bit integer)

   scalar = $event->cur
   scalar = $event->cur_type
   scalar = $event->flags
   scalar = $event->format
   scalar = $event->rate
   scalar = $event->stop
   scalar = $event->stop_type
ENUMS AND FLAGS

   enum GStreamer::Format
       o   'undefined' / 'GST_FORMAT_UNDEFINED'

       o   'default' / 'GST_FORMAT_DEFAULT'

       o   'bytes' / 'GST_FORMAT_BYTES'

       o   'time' / 'GST_FORMAT_TIME'

       o   'buffers' / 'GST_FORMAT_BUFFERS'

       o   'percent' / 'GST_FORMAT_PERCENT'

   flags GStreamer::SeekFlags
       o   'none' / 'GST_SEEK_FLAG_NONE'

       o   'flush' / 'GST_SEEK_FLAG_FLUSH'

       o   'accurate' / 'GST_SEEK_FLAG_ACCURATE'

       o   'key-unit' / 'GST_SEEK_FLAG_KEY_UNIT'

       o   'segment' / 'GST_SEEK_FLAG_SEGMENT'

       o   'skip' / 'GST_SEEK_FLAG_SKIP'

   enum GStreamer::SeekType
       o   'none' / 'GST_SEEK_TYPE_NONE'

       o   'cur' / 'GST_SEEK_TYPE_CUR'

       o   'set' / 'GST_SEEK_TYPE_SET'

       o   'end' / 'GST_SEEK_TYPE_END'

SEE ALSO

       GStreamer

COPYRIGHT

       Copyright (C) 2005-2011 by the gtk2-perl team.

       This software is licensed under the LGPL.  See GStreamer for a full notice.

perl v5.14.2							    2012-03-01					       GStreamer::Event::Seek(3pm)
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