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Date:      Mon, 12 Dec 2005 09:33:37 +0530
From:      rashmi ns <nsrashmi@gmail.com>
To:        freebsd-hackers@freebsd.org, freebsd-drivers@freebsd.org
Subject:   Help Reqd: "uiomove" transferring zero bytes from user-kernel space
Message-ID:  <9f9993160512112003i56f25cd6t78533717fec580d1@mail.gmail.com>
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Hello Team,
                  when i use  "uiomove"  in the character device
interface the no of bytes transfrerred between kernel and userspace is
zero .but the actual data transferred when trraced through
"uio->resid" is correct .can  any one explain why this is happening ?

/*Character Device Interfaces*/
static struct cdevsw  hdlc_cdevsw = {

        .d_maj      = CDEV_MAJOR,
        .d_open     = hdlc_open,
        .d_read     = hdlc_read,
        .d_write     = hdlc_write,
        .d_ioctl    = hdlc_ioctl,
        .d_close    = hdlc_close,
        .d_version  = D_VERSION,
};
static int hdlc_write(dev_t dev, struct uio *uio, int ioflag)
{
        int     towrite,written;  /*char device inf*/
     written=uiomove((void *)write_tx_buffer,towrite,uio);
     uprintf("uio->resid=%d",uio->uio_resid);
    uprintf("No of bytes written  =%d",written);




}

Thanks and Regards,
Rashmi.N.S
help

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