Mail Archives: cygwin/2005/10/22/09:33:27
Corinna Vinschen <corinna-cygwin <at> cygwin.com> writes:
>
> On Oct 22 07:06, Todd Rearick wrote:
> > while(1)
> > {
> > char buf[80];
> > int len;
> >
> > len = recv(infd,buf,1,0);
> >
> > if (len < 1)
> > {
> > printf("len = %d\n",len);
> > printf("errno = %d\n",errno);
> > printf("This means %s\n", strerror(errno));
> > sleep(1);
>
> What you're entirely missing at this point is the fact that a return
> value of 0 (zero) indicates EOF. You don't test for this. Instead
> you're also testing errno in case of EOF, which has no meaning in this
> case.
>
> Corinna
>
hmm...good point (and you are correct)....Here is the full program output
(well...up until I hit Ctrl-C)
Connecting to localhost:8080
Redirecting output to COM4
len = 0
errno = 119
This means Operation now in progress
len = 0
errno = 119
This means Operation now in progress
len = 0
errno = 119
This means Operation now in progress
....etc....
The only reason I ever checked errno was because I was trying to get more
information as to why it wasn't receiving the data....You're right
though...the errno=119 must be from something earlier in the program...and
maybe that is a clue....but (as you can see from the code) I check the returns
of all previous calls and none fail when I run the code.
After further testing...it looks like the "connect" call sets errno...even
though it's return value indicated no error occured....The other end of the
socket also "thinks" it is connected.
My *NEW* question is this then: Why do I get len = 0 over and over. I never
receive a character (even when I know one was transmitted). The read first
blocks (as it should)...until the first character is sent...and then it starts
bailing out immediately with len=0 over and over...and I never do receive the
character I sent in the other end of the pipe.
Thanks again for all your help,
Todd
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