# Using file descriptor sink? **URL:** \ **Category:** GNU Radio\ **Created:** [May 30, 2014, 5:20pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101 "2014-05-30T17:20:28Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jason\_sam](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7993a0/32.png) [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Post date:** [May 30, 2014, 5:20pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/1 "2014-05-30T17:20:28Z")
Hello GR, Can anyone please give me some hints on how to use gr-file descriptor sink in a gnuradio python flowgraph. Regards, Ruecan – View this message in context: [http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640.html](http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 5:51pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/2 "2014-05-30T17:51:33Z")
Hi Ruecan, if you’re asking this question, you probably shouldn’t use file\_descriptor\_sink. It works quite like file\_sink, but instead of a filename, you pass a file descriptor, which is the int handler the open() syscall will return. Greetings, Marcus ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 6:04pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/3 "2014-05-30T18:04:27Z")
Ah sorry, forgot the important part: If you have opened a file from python, let’s say by: myfile = open("/home/ruecan/secretplanforworlddominance.pdf", “r”) you can get the file descriptor by doing fd = myfile.fileno() Greetings, Marcus ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 6:16pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/4 "2014-05-30T18:16:46Z")
My question is let say I have this socket ``` self.blocks_socket_pdu_0_Rx = blocks.socket_pdu("UDP_CLIENT", ``` “localhost”, “4000”, 10000) And then I need to associate a file descriptor to it. How can I have the int handler like the open() syscall would return ? ``` self.myFileDescriptor = blocks.file_descriptor_sink(2048, ??) ``` Ruecan. – View this message in context: [http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48644.html](http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48644.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 6:26pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/5 "2014-05-30T18:26:44Z")
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Sorry, I don’t understand. Could you rephrase/elaborate on that? Where does the file descriptor come into play? On 30.05.2014 18:15, Ruecan wrote: > Ruecan. > > – View this message in context: > [http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48644.html](http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48644.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio > mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - [http://www.enigmail.net/](http://www.enigmail.net/) iQEcBAEBAgAGBQJTiLDtAAoJEBQ6EdjyzlHtsaQIAKlg6oAbSxm+MM7U5nkDm1sQ ppsjH7wuLB1IjocpLjDonIrXDEJDzzTpOxdT7p3LJUgujUHs9pKAq+W7IdccRy+u J1KzKYrvbdjOoWbpBVMymJ6IjkuTOYrlQKEOB9Z1sd73Y3zkhKYk8+HYx+nPXd2O 76BY6AqvWEAlBl7VQTqR+dx/v5M5rU90eyanBN25A+V8lieUeU7s6D0qvcpsNuQZ 35Qfdg5mTIcduc0k5k02l7HQAr+dXkTveqhRKlnffXIFPccMp1vrrYbQQlLMCKPJ vSlfc+a7+uYvSOzjV6Tckbiux5oGOMn3EiTUhgJzLX8UY67a9VzKmd7YGnrwxmw= =NeMU -----END PGP SIGNATURE----- ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 7:48pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/6 "2014-05-30T19:48:10Z")
I mean if I try this: > self.blocks\_socket\_pdu\_0\_Rx = blocks.socket\_pdu(“UDP\_CLIENT”, “localhost”, > “4000”, 10000) > self.myFileDescriptor = blocks.file\_descriptor\_sink(2048, > open(self.blocks\_socket\_pdu\_0\_Rx, ‘r+b’)) I got: TypeError: coercing to Unicode: need string or buffer, socket\_pdu\_sptr found I don’t know how to get a file descriptor out of that to read it and retrieve packets received. – View this message in context: [http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48647.html](http://gnuradio.4.n7.nabble.com/Using-file-descriptor-sink-tp48640p48647.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![naeo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/57b2e6/32.png) [@naeo](https://www.ruby-forum.com/u/naeo)\ **Post date:** [May 30, 2014, 8:02pm UTC](https://www.ruby-forum.com/t/using-file-descriptor-sink/230101/7 "2014-05-30T20:02:14Z")
I think you’re mixing things up. open() like you use it is a call to generate a python “file” object, which is not the file descriptor a file\_destructor\_sink needs. open() expects a string, but you offer a socket\_pdu shared pointer (ie. the python (swig) representation of the C++ block of that name). I don’t really understand what you are trying to do; could you explain? I’m fairly certain file\_descriptor\_sink is not what you want… Greetings, Marcus