Kurt Van Dijck wrote:
> On Mon, Sep 21, 2009 at 10:30:07AM +0200, [email protected] wrote:
>> Hello Wolfgang,
>>
>> I have tested SW again and cannot reproduce error situation I had
>> yesterday.
>> Everything turns out to be OK. Was it Sunday effect? I have no idea...
>> The write function issue you have mentioned is fixed (see attached).
> I looked at the code.
>
> while( (nbytes=write(s, &tx_frames[send_pos],
> sizeof(*tx_frames))) !=
> sizeof(*tx_frames) )
> {
> if(nbytes!=EAGAIN)
> {
> perror("write");
> return 1;
> }
> }
>
> I don't know the exact purpose of the test.
> This loops asks for sunday effects, isn't it?
>
> nbytes would return -1, not EAGAIN!
> if ((nbytes < 0)&&(EAGAIN == errno))
With proper error handling it should look like:
if (nbytes < 0) {
if (errno == ENOBUFS)
continue;
perror("write failed");
} else {
fprintf(stderr, "write returned bogus %d\n", nbytes);
}
return 1;
> is what I think you meant
Ah, oh, sure, missed that :-(. Thanks for pointing that out.
> my preference:
>
> int ret;
> struct pollfd pollfd;
>
> pollfd.fd = s;
> pollfd.events = POLLOUT;
> while ((ret = poll(&pollfd, 1, -1)) < 0) {
> if (EAGAIN == errno) {
> perror("write");
> return 1;
> }
> }
> nbytes = write(s, ....)
> // nbytes with anything other than sizeof(*tx_frames) is a serious
> // poll issue
>> Regards,
>> Vladislav
As Marc pointed out, poll/select will block in case of ENOBUFS.
Wolfgang.
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