Re: Blocking read() from a USB->Serial adapter.

Grant Edwards <grante@xxxxxxxx> writes:
On 2006-11-25, Floyd L. Davidson <floyd@xxxxxxxxxx> wrote:
Grant Edwards <grante@xxxxxxxx> wrote:
On 2006-11-25, Charles Sullivan <cwsulliv@xxxxxxxxxxxx> wrote:

If that's the case, then that answers my questions. I thought
blocking meant blocking until the specified number of
characters is read, or until the read is interrupted.

Or until the driver decides to return for whatever reason it
chooses. On success, you're guaranteed a minimum of one byte.

Maybe. (Maybe not too!)

There's the case where the file is at EOF. Is there another
case where read() will return success with 0 bytes?

Yes. A non-blocking read from a UDP socket can return 0 octets read
instead of EAGAIN (at least on some Linux 2.4 versions).
.

Relevant Pages

  • Re: Blocking read() from a USB->Serial adapter.
    ... blocking meant blocking until the specified number of ... Or until the driver decides to return for whatever reason it ... On success, you're guaranteed a minimum of one byte. ... indeed set the EOF flag, but with a serial port (or a pipe, or a ...
    (comp.os.linux.development.apps)
  • Re: Blocking read() from a USB->Serial adapter.
    ... returning fewer characters than specified if the characters ... But I had the impression that a blocking read is supposed to block ... available (e.g. if some disk has to position its head first, ... both return all data the driver has available for you at ...
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  • Re: Blocking read() from a USB->Serial adapter.
    ... blocking meant blocking until the specified number of ... Or until the driver decides to return for whatever reason it ... On success, you're guaranteed a minimum of one byte. ...
    (comp.os.linux.development.apps)
  • Re: Blocking read() from a USB->Serial adapter.
    ... blocking meant blocking until the specified number of ... characters is read, or until the read is interrupted. ... Or until the driver decides to return for whatever reason it ...
    (comp.os.linux.development.apps)
  • Re: Blocking read() from a USB->Serial adapter.
    ... Grant Edwards wrote: ... blocking meant blocking until the specified number of ... characters is read, or until the read is interrupted. ... Or until the driver decides to return for whatever reason it ...
    (comp.os.linux.development.apps)