Re: R: getsockopt(SO_KEEPALIVE) returns incorrect option length

[Pavel Holejsovsky <pavel dot holejsovsky at upek dot com>]

On 7/2/2010 12:01 PM, Marco Atzeri wrote:
> --- Ven 2/7/10, Pavel Holejsovsky ha scritto:
>
> > Hi,
> >
> > I think that following problem shows problematic behavior
> > in cygwin 1.7.5, at least incompatible with linux:
> >
> > #include<stdio.h>
> > #include<sys/socket.h>
> >
> > int main() {
> >          int sock, option, optlen =
> > sizeof(int);
> >          sock = socket(AF_INET,
> > SOCK_STREAM, 0);
> >          getsockopt(sock, SOL_SOCKET,
> > SO_KEEPALIVE,&option,&optlen);
> >          printf("option=%d,
> > optlen=%d\n", option, optlen);
> >          return 0;
> > }
> >
> > Prints optlen=1, while it is expected to be sizeof(int),
> > i.e. 4.
> >
> > This is most probably because uinderlying winsock call has
> > this (mis)behavior, but I think that in cygwin layer this
> > could be worked around to be more unix compatible.
> >
> > This issue is relevant:
> >
> > SO_KEEPALIVE value is actually a char on Windows, not BOOL
> > https://bugzilla.gnome.org/show_bug.cgi?id=611756
> >
> > And causes glib gio 2.24 to fail certain socket operations
> > on cygwin.
> >
> > thanks,
> > Pavel
>
> option=0, optlen=4
>
> on XP-sp2, cygwin 1.7.5s(0.227/5/3) 20100628

Thanks for testing, Marco.

So it is even system-dependent misbehaviour of winsock.  On w7-x64 
cygwin 1.7.5 it prints
option=2674688, optlen=1

Pavel


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