Comment 11 for bug 386558

Wouldn't it be reasonable to range-check the file descriptor when security-related feature test macros (perhaps FORTIFY_SOURCE) are enabled?

By the way, POSIX specifies that passing fd values greater than or equal to FD_SETSIZE to the FD_* macros/functions results in undefined behavior, so programs which want to *try* using select with higher fds should do it by allocating an *array of fd_set objects* with (maxfd+FD_SETSIZE)/FD_SETSIZE elements, then performing operations like FD_SET(fd%FD_SETSIZE, &fds[fd/FD_SETSIZE]); -- this also avoids dependency on nonstandard and nonportable macros like NFDBITS.