connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
"network" orders. These are guaranteed to be portable.
+As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
+to force big- or little-endian byte-order. This is useful if you want
+to store signed integers or 64-bit integers, for example.
+
You can explore the endianness of your platform by unpacking a
data structure packed in native format such as:
Don't assume that you can reach outside world through any other port
than 80, or some web proxy. ftp is blocked by many firewalls.
+Don't assume that you can send email by connecting to the local SMTP port.
+
Don't assume that you can reach yourself or any node by the name
-'localhost'. The same goes for '127.0.0.1'. You will have to try
-both.
+'localhost'. The same goes for '127.0.0.1'. You will have to try both.
Don't assume that the host has only one network card, or that it
can't bind to many virtual IP addresses.
Don't assume a particular network device name.
-Don't assume that any particular port (service) will respond.
+Don't assume a particular set of ioctl()s will work.
Don't assume that you can ping hosts and get replies.
+Don't assume that any particular port (service) will respond.
+
+Don't assume that Sys::Hostname() (or any other API or command)
+returns either a fully qualified hostname or a non-qualified hostname:
+it all depends on how the system had been configured. Also remember
+things like DHCP and NAT-- the hostname you get back might not be very
+useful.
+
All the above "don't":s may look daunting, and they are -- but the key
is to degrade gracefully if one cannot reach the particular network
service one wants. Croaking or hanging do not look very professional.
What C<\n> represents depends on the type of file opened. It usually
represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
-C<\000>, C<\040>, or nothing depending on the file organiztion and
+C<\000>, C<\040>, or nothing depending on the file organization and
record format. The VMS::Stdio module provides access to the
special fopen() requirements of files with unusual attributes on VMS.
C<-x> (or C<-X>) determine if a file has an executable file type.
(S<RISC OS>)
-=item alarm SECONDS
-
-=item alarm
-
-Not implemented. (Win32)
-
=item binmode FILEHANDLE
Meaningless. (S<Mac OS>, S<RISC OS>)