Re: [Discuss-gnuradio] Writing baseband data from the USRP

[Eric Blossom]

On Thu, Feb 02, 2006 at 02:46:51PM -0500, Marcus Leech wrote:
> I want to be able to write baseband data from the usrp to a file.  So I 
> can just use
>  gr_file_sink or gr_file_descriptor_sink as appropriate.
> 
> But I want to have the GUI have a "start recording" and "stop recording"
>  control that turns on/off the "torrent" of data to the disk, create 
> filenames
>  dynamically, etc.
> 
> Any suggestions?

I've used this fairly hideous kludge to good effect:

# at init time...

self.log_file = open('/dev/null', 'w')   # hold ref to file so it stays open
self.log_fd = self.log_file.fileno()     # get the file descriptor
log = gr.file_descriptor_sink(gr.sizeof_foo, self.log_fd)


# Some time later...

new_file = open('/path/to/logfile', 'w')  # open new target file
os.dup2(new_file.fileno(), self.log_fd)   # self.log_fd now refs new_file
self.log_file = new_file                  # hold on to new file so it stays open


Eric