Re: Changing the output file of 'File sink' block automatically

Hei Kimmo,

Take this with a pinch of salt because it has been ~3 years since I worked with GNU radio but I think I can answer this based on my experience of hosting Swift app on Linux.

I'm assuming a little bit of latency isn't an issue.

Perhaps we could write a custom block, which as you said will act as buffer during file name change. The File Sink block thread could be paused momentarily, and then the following commands are executed:

cp outputFile archive-dd-mm-yyyy.ext

echo "" > outputFile

Then resume the paused thread?

Obviously if the file is very large, there can be latency. Probably not the best way to do.

I use to build gnu-radio from source. So personally I wouldn't hesitate to make a derivative of that file sink block if necessary and possible.

Hope it helps.

Terveisin,

Kaushik

On Wed, Apr 9, 2025, 01:49 Kimmo Lehtinen <kimmo.lehtinen@yahoo.fi> wrote:

Hi

We are using the 'File sink' block to continuously stream data to output file. 

We want to change the name of the output file automatically, once a day. 

We could modify the Python program produced by GRC, as suggested at 

https://lists.gnu.org/archive/html/discuss-gnuradio/2017-05/msg00190.html

That method involves disconnecting the 'file sink' block, changing the name of the output file, and then connecting the file sink block again. But this means that we would miss some samples, which we do not want to do. 

Should we save the data into a buffer just before disconnecting the 'file sink' block, and then empty the buffer after the file sink block has been connected ?

We are using the Ettus USRP N210 receiver.

Cheers, Kimmo