[Bluez-users] error while making call to ioctl for releasing a device

hi,
   I am trying to obex push a file through rfcomm channel. Everything goes
fine (including sending of file) until i try to release the device via call
to ioctl

exact call is

ioctl(sock,RFCOMMRELEASEDEV,&req)

with error  " Bad File Descriptor".

Can anyone give me a hint abt why can this happen..
Waiting for some reply

regards
siddhant