[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Details on USB buffer
From: |
Stefan Bruens |
Subject: |
Re: [Discuss-gnuradio] Details on USB buffer |
Date: |
Fri, 27 Feb 2009 12:43:08 +0100 |
User-agent: |
KMail/1.11.0 (Linux/2.6.27.7-9-mtrr_san; KDE/4.2.0; x86_64; ; ) |
On Friday 27 February 2009 01:05:52 Tony wrote:
> The USRP C++ example program uses this code to move USRP USB data into a
> buffer:
>
> urx->read(&buf, bufsize, &overrun);
>
> If this line is called many times in a short period of time will the buffer
> have some of the data leftover from previous read(s)? Can I assume that
> the OS will not return the buffer until the next n bytes have been
> received?
>
> Tony
The read is a blocking read. The return value is the number of bytes actually
read, which will always be the same as bufsize or an error value (<0). Samples
may be thrown away in the USRP itself this is called an overrun, in this case
the corresponding variable will be set to true.
Stefan
--
Stefan Brüns / Bergstraße 21 / 52062 Aachen
phone: +49 241 53809034 mobile: +49 151 50412019