Hi,
I have now proceeded to create non blocking IO channels but can't get your select() implementation to work. The problem is that it doesn't timeout as it should and therefore act as a blocking IO.
int selectOnRead(int sockfd, unsigned long secTimeout, unsigned long uTimeout)
{
fd_set readFdSet;
struct timeval tv;
tv.tv_sec = secTimeout;
tv.tv_usec = uTimeout;
FD_ZERO(&readFdSet);
FD_SET(sockfd, &readFdSet);
select(FD_SETSIZE, &readFdSet, NULL, NULL, &tv)
}
The code above is as simple as it gets by using select; only one file descriptor that should timeout on the values set in "tv". If we go through the arguments to select they should be:
- FD_SETSIZE = Number of FDs + 1 (Or FD_SETSIZE)
- readFdSet = Array of FDs to observe when they can be read without blocking
- tv = A simple time structure that can hold seconds and microseconds
(If tv is NULL select will block, if both time holders are 0 select return immediately, else it will use the values for timeout - http://www.gnu.org/software/libc/manual/html_mono/libc.html#Waiting-for-I_002fO)
I have tested the following:
1. If both time holders in tv is set to 0 VMCI-socket still blocks.
2. It doesn't matter if datagram or stream is used.
3. If all three observable types is NULL select will not block (or timeout) but instead return error(-1).
No matter what I put into the arguments it will block until a client sends it a packet. Is this a known bug or are my implementation wrong?
For a more complete example see the server implementation in the attachment.
Kind Regards
Andreas
