From david.dyck@fluke.com

Created by david.dyck@fluke.com

The example given in perldoc -f getsockopt​:

  use Socket;

  defined(my $tcp = getprotobyname("tcp"))
  or die "Could not determine the protocol number for tcp";
  # my $tcp = Socket​::IPPROTO_TCP; # Alternative
  my $packed = getsockopt($socket, $tcp, Socket​::TCP_NODELAY)
  or die "Could not query TCP_NODELAY SOCKEt option​: $!";
  my $nodelay = unpack("I", $packed);
  print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";

is incorrect, it should declare the constant it intends to import
 
I think there is a bug in the documentation that the example may
not get the value of TCP_NODELAY without changing the
  use Socket;
to
  use Socket qw(TCP_NODELAY);
  or
  use Socket qw(​:all);

$ perl -wle 'use Socket; print STDOUT Socket​::TCP_NODELAY'
Socket​::TCP_NODELAY

That was unexpected!!!!!!
either it needs to be called as a function, or imported directly

$ perl -wle 'use Socket; print STDOUT Socket​::TCP_NODELAY()'
1
$ perl -wle 'use Socket; print STDOUT &Socket​::TCP_NODELAY'
1
$ perl -wle 'use Socket qw(TCP_NODELAY); print STDOUT TCP_NODELAY'
1

There is probably a similar error in the alternative use of Socket​::IPPROTO_TCP

I'm not sure why, but the examples use symbols that are in @​EXPORT_OK
and must be imported by the tag :all, or listed explicitly
Not only TCP_NODELAY and IPPROTO_TCP, but also
TCP_KEEPALIVE, TCP_MAXRT, TCP_MAXSEG, TCP_STDURG

There is no mention in the documentation for Socket that suggests
that the user needs to import these symbols. (the :crlf tag IS
documented though)

Flags:
    category=docs
    severity=low

Site configuration information for perl v5.9.2:

Configured by dcd at Mon Feb 14 11:46:39 PST 2005.

Summary of my perl5 (revision 5 version 9 subversion 2 patch 23965) configuration:
  Platform:
    osname=linux, osvers=2.4.30-pre1, archname=i686-linux
    uname='linux dd 2.4.30-pre1 #1 wed feb 9 18:15:26 pst 2005 i686 '
    config_args='-Accflags=-DPERL_DISABLE_PMC -Dmksymlinks -Dinstallusrbinperl -Uversiononly -Dusedevel -Doptimize=-O3 -g -de -Dcf_email=david.dyck@fluke.com'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useithreads=undef usemultiplicity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-DPERL_DISABLE_PMC -DDEBUGGING -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O3 -g',
    cppflags='-DPERL_DISABLE_PMC -DDEBUGGING -fno-strict-aliasing -pipe -I/usr/local/include'
    ccversion='', gccversion='egcs-2.91.66.1 19990314/Linux (egcs-1.1.2 release)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=4
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lgdbm -ldbm -ldb -ldl -lm -lc
    perllibs=-ldl -lm -lc
    libc=/lib/libc.so.5.4.44, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    DEVEL22511


@INC for perl v5.9.2:
    /usr/local/lib/perl5/5.9.2/i686-linux
    /usr/local/lib/perl5/5.9.2
    /usr/local/lib/perl5/site_perl/5.9.2/i686-linux
    /usr/local/lib/perl5/site_perl/5.9.2
    /usr/local/lib/perl5/site_perl
    .


Environment for perl v5.9.2:
    HOME=/home/dcd
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/dcd/bin:/sbin:/usr/local/bin:/bin:/usr/bin:/usr/X11/bin:/usr/games:/usr/local/samba:/home/hobbes/tools/scripts:/home/hobbes/tools/linux:/usr0/hobbes/tools/scripts:/usr0/dcd/bin:/apps/general/bin:/usr/public
    PERL5_CPANPLUS_CONFIG=/home/dcd/.cpanplus/config
    PERL_BADLANG (unset)
    SHELL=/bin/bash

From @rgs

David Dyck (via RT) wrote​:

The example given in perldoc -f getsockopt​:
...
is incorrect, it should declare the constant it intends to import

I applied the fix below :

==== //depot/perl/pod/perlfunc.pod#453 (text) ====

@​@​ -2115,13 +2115,13 @​@​

An example testing if Nagle's algorithm is turned on on a socket​:

- use Socket;
+ use Socket qw(​:all);

  defined(my $tcp = getprotobyname("tcp"))
  or die "Could not determine the protocol number for tcp";
- # my $tcp = Socket​::IPPROTO_TCP; # Alternative
- my $packed = getsockopt($socket, $tcp, Socket​::TCP_NODELAY)
- or die "Could not query TCP_NODELAY SOCKEt option​: $!";
+ # my $tcp = IPPROTO_TCP; # Alternative
+ my $packed = getsockopt($socket, $tcp, TCP_NODELAY)
+ or die "Could not query TCP_NODELAY socket option​: $!";
  my $nodelay = unpack("I", $packed);
  print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";

The RT System itself - Status changed from 'new' to 'open'

@rgs - Status changed from 'open' to 'resolved'