weird select() problem on FreeBSD

[nslay]

While pondering FreeBSD socket programming I created a simple program that connects to battle.net, logs in, and spits out everything bnet sends.
I originally wanted to use select so I could read the keyboard and the socket at the same time (none of that "fancy" MS socket stuff is on Unix of course)
I don't have the code in front of me, but I basically did this

Assume the connection was already established and 0x03 was sent

fd_set reads;
FD_ZERO(&reads);
FD_SET( sock, &reads );

while( select( 1, &reads, 0, 0, 0 ) > 0 ) {
//Do some cool stuffs here   ... but not really because it doesn't work! 
}

now, of course I used select as a loop condition, when positive continue looping, else die!  This is just an example.  Now, I am aware I put a null pointer for the time parameter, I want it to be indefinate blocking ... however, it should return 1 when the socket recieves data even though it is indefinate blocking   

Again, select appears to screw up since recv does the job just fine.
Now, either select is fudged or sockets aren't fds (which I am pretty sure they are)

[OnlyMeat]

Shouldn't the first parameter for select be the actual socket returned from a socket() call?. You shouldn't be using a fixed value of 1 surely.

You could try doing something like this:

Code Select Expand


select(sock, &rread, (fd_set *)0, (fd_set *)0, &to);


to is a struct timeval;

[nslay]

Shouldn't the first parameter for select be the actual socket returned from a socket() call?. You shouldn't be using a fixed value of 1 surely.

You could try doing something like this:

Code Select Expand


select(sock, &rread, (fd_set *)0, (fd_set *)0, &to);


to is a struct timeval;

http://www.freebsd.org/cgi/man.cgi?query=select&apropos=0&sektion=0&manpath=FreeBSD+5.4-RELEASE&format=html
no, you stick the socket inside of a fd_sets variable, the first parameter is the number of file descriptors to check... in this case 1

[NicoQwertyu]

Last time I remember using select(), the first parameter had to be the highest descriptor in the set + 1.

[NicoQwertyu]

ERRORS
     An error return from select() indicates:

     [EBADF]One of the descriptor sets specified an invalid
descriptor.

     [EFAULT]One of the arguments readfds, writefds, exceptfds, or
timeout points to an invalid address.

     [EINTR]A signal was delivered before the time limit expired
and before any of the selected events occurred.

     [EINVAL]The specified time limit is invalid.  One of its com-
ponents is negative or too large.

     [EINVAL]The nfds argument was invalid.

Perhaps try changing your while loop to check for errors as well.  Maybe something else is going on.

Edit: Nevermind.  Re-read your post and saw that it's blocking indefinently.

[nslay]

Shouldn't the first parameter for select be the actual socket returned from a socket() call?. You shouldn't be using a fixed value of 1 surely.

You could try doing something like this:

Code Select Expand


select(sock, &rread, (fd_set *)0, (fd_set *)0, &to);


to is a struct timeval;

This is slightly correct actually.  It turns out that fd_sets are just bitfields and when FD_SET is used, it just switches that bit on at the fd's value.  When I ran it, the socket returned was 3, this turned on the 4th bit in the field so in order for select to work, the first parameter would have to be 4 since it checks the first 0 - n-1 bits in the field.

[NicoQwertyu]

Aha! I prevail!

... the first parameter had to be the highest descriptor in the set + 1.

[nslay]

Aha! I prevail!

... the first parameter had to be the highest descriptor in the set + 1.

Moo