=over =item fcntl FILEHANDLE,FUNCTION,SCALAR Implements the fcntl(2) function. You'll probably have to say use Fcntl; first to get the correct constant definitions. Argument processing and value return works just like C below. For example: use Fcntl; fcntl($filehandle, F_GETFL, $packed_return_buffer) or die "can't fcntl F_GETFL: $!"; You don't have to check for C on the return from C. Like C, it maps a C<0> return from the system call into C<"0 but true"> in Perl. This string is true in boolean context and C<0> in numeric context. It is also exempt from the normal B<-w> warnings on improper numeric conversions. Note that C will produce a fatal error if used on a machine that doesn't implement fcntl(2). See the Fcntl module or your fcntl(2) manpage to learn what functions are available on your system. =back