<<On Fri, 21 May 2004 12:13:14 -0400, "Green, Paul" <yyyyyyyyyy@xxxxxxxxxxx>
said:
> What does the phrase "all bits" mean? Does it mean the "first nfds bits" or
> does it mean "all bits"?
The traditional implementation permits applications to redefine the
macro FD_SETSIZE before including any of the headers that may cause
the fd_set type to be defined, to indicate the maximum number of file
descriptors the application may want to access. Therefore, those
implementations cannot access more than ROUNDUP(nfds, sizeof
base_type_of_fd_set) bits.
Of course, the poll() interface avoids this problem, but is even more
horribly inefficient for large numbers of descriptors. Nonstandard
interfaces such as kqueue() resolve this issue, but new applications
will typically use threads instead.
-GAWollman
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