>from linux/posix_types/h: >#undef __FD_SETSIZE >#define __FD_SETSIZE 1024 > >Well, you *can* change it, but it requires a recompile of the kernel and >all userland programs that create an fd_set. Which is generally true for most Unix systems; traditionallly you can redefine FD_SETSIZE for a larger set but you're limited by kernel support (or libc support, as the case may be) >In this regard, windows did get it right. However, the earlier comment >on using the windows async sockets is spot on, if you want performance. >Windows fd_set's are structured more like unix poll() arrays (un-ordered >array of fd's) and are not very efficient if there are many sockets on >one set. Also, a linux fd_set limits the fd *value* to < 1024, not just >the number of fd's in the set. So it's possible to only want to put one >fd on a fd_set but be unable to do so if it's value is > FD_SETSIZE >(which can be done by increasing the maximum number of file handles a >process is permitted to open). Which is why poll(2) is the superior interface; but event driven machnisms are in the end the best. Casper
