Re: named fifo (byte - byte transfer)

[CEL]

Hi,

we've covered pretty much exactly your three questions in a mailing
list thread earlier this month. Let me link to the archive:

https://lists.gnu.org/archive/html/discuss-gnuradio/2019-10/index.html

It's the mails with subject "fifo / file source".

In essence, "cat" is buffered, and so you need to use a different
program that makes sure the fstream it outputs is unbuffered. GNU Radio
has no influence on the buffering your writing process does.

Best regards,
Marcus

On Wed, 2019-10-30 at 14:19 +0200, hamzeh elsayed wrote:
> Hi,
> 
> I did the following:
> 1) in linux terminal I create a fifo file as : 
>     $ mkfifo in
> 2) in gnuradio I did:
> file source (file name : in)-> throttle -> file sink (output file: out.txt)
> 
> 
> 
> then for running, I did the following:
> 1) run the flowgraph
> 2) in terminal, I run
>     $ cat > in
> 
> then only if I wrote a large number for characters, those characters are 
> transferred.
> 
> for example if I wrote 10 bytes in fifo in to transmit them, any byte is not 
> written in the file out.txt. while, if 15000 bytes are written in fifo in the 
> some of these 15000 bytes are transferred to out.txt but not all of them.
> 
> it seems to me that fifo in gnuradio does not transfer each byte alone, is 
> saves a number of bytes as a packet then it send them together.
> 
> my question is :
> 
> 1) how to transfer each byte alone in my flowgraph example using unix pipe?
> 
> 2) if I can not transfer each byte alone, what is the size of packet that are 
> buffered and the transferred together?
> 
> 3) If the last bytes are less than packet size, then they are not 
> transferred. therefore, how I can I transfer them? 
> 
> if I have to do padding then I have to know the size of the buffer or packet? 
> Is it fixed or not?
> 
> Thanks for your time and help
> 
> Best regards

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