Okay, I should have probably read h2xs before asking this.

Oct 29 16:42 UTC 2006

I tried reading the linux internal documentation, but couldn't find the answer
to the following:

When I use CGI, I go something like the following:

#!/usr/local/bin/perl -w
use CGI;                             
$q = new CGI;                        
print $q->header,                    
      $q->start_html('hello world'), 
      $q->h1('hello world'),         
      $q->end_html;                  

The way I understand it, $q holds the reference to new(). This reference is
then passed to functions like header(), start_html(), etc.

The confusion stems from the socket module. According to the man pages, it
goes like:

use Socket;
$proto = getprotobyname('tcp');
           socket(Socket_Handle, PF_INET, SOCK_STREAM, $proto);
           $port = getservbyname('smtp', 'tcp');
           $sin = sockaddr_in($port,inet_aton("127.1"));
           $sin = sockaddr_in(7,inet_aton("localhost"));
           $sin = sockaddr_in(7,INADDR_LOOPBACK);
           connect(Socket_Handle,$sin);

In this case, there is no pass by reference. Why? I'm drawing a blank.

The man pages made a comment that this module is just translation of the C
socket.h file. Is this part of the reason? 

response 2 of 11:

Oct 29 19:40 UTC 2006

Okay, I sat down and thought about this (sort of). Anyhow, here is what is
nagging at me worse than nharmons moms cheap pantyhose.

These lines:
$sin = sockaddr_in($port,inet_aton("127.1"));
            $sin = sockaddr_in(7,inet_aton("localhost"));
            $sin = sockaddr_in(7,INADDR_LOOPBACK);
 are in Socket.pm

Perl doesnt bitch if I do something like:
#!/usr/bin/perl -w

use Socket;

$proto = getprotobyname('udp');
socket(Socket_Handle, PF_INET, SOCK_DGRAM, $proto);
$iaddr = gethostbyname('hishost.com');
$port = getservbyname('time', 'udp');
$sin = Socket::sockaddr_in($port, $iaddr);
send(Socket_Handle, 0, 0, $sin);

Where is gethostbyname() coming from? There is no prototype in the C socket.h
header file.

response 4 of 11:

Oct 29 23:56 UTC 2006

Yeah, but like netdb.h header doesn't get called in the Perl code. The module
only translates the socket.h header. So how is the code finding
gethostbyname() in this case?

response 6 of 11:

Oct 30 00:57 UTC 2006

 If you read "perldoc Socket" it says that in addition to the stuff derived
 from socket.h, Socket contains some additional functions.  My guess is that
 although it's not specifically mentioned in that part the Perl gethostbyname
 is implemented as a combination of some of those calls (e.g. inet_aton)

response 8 of 11:

Oct 30 01:53 UTC 2006

Here is Socket.pm. Please tell me where gethostbyname() is.

use Carp;
use warnings::register;

require Exporter;
use XSLoader ();
@ISA = qw(Exporter);
@EXPORT = qw(
        inet_aton inet_ntoa
        sockaddr_family
        pack_sockaddr_in unpack_sockaddr_in
        pack_sockaddr_un unpack_sockaddr_un
        sockaddr_in sockaddr_un
        INADDR_ANY INADDR_BROADCAST INADDR_LOOPBACK INADDR_NONE
        AF_802
        AF_AAL
        AF_APPLETALK
        AF_CCITT
        AF_CHAOS
        AF_CTF
        AF_DATAKIT
        AF_DECnet
        AF_DLI
        AF_ECMA
        AF_GOSIP
        AF_HYLINK
        AF_IMPLINK
        AF_INET
        AF_INET6
        AF_ISO
        AF_KEY
        AF_LAST
        AF_LAT
        AF_LINK
        AF_MAX
        AF_NBS
        AF_NIT
        AF_NS
        AF_OSI
        AF_OSINET
        AF_PUP
        AF_ROUTE
        AF_SNA
        AF_UNIX
        AF_UNSPEC
        AF_USER
        AF_WAN
        AF_X25
        IOV_MAX
        MSG_BCAST
        MSG_BTAG
        MSG_CTLFLAGS
        MSG_CTLIGNORE
        MSG_CTRUNC
        MSG_DONTROUTE
        MSG_DONTWAIT
        MSG_EOF
        MSG_EOR
        MSG_ERRQUEUE
        MSG_ETAG
        MSG_FIN
        MSG_MAXIOVLEN
        MSG_MCAST
        MSG_NOSIGNAL
        MSG_OOB
        MSG_PEEK
        MSG_PROXY
        MSG_RST
        MSG_SYN
        MSG_TRUNC
        MSG_URG
        MSG_WAITALL
        MSG_WIRE
        PF_802
        PF_AAL
        PF_APPLETALK
        PF_CCITT
        PF_CHAOS
        PF_CTF
        PF_DATAKIT
        PF_DECnet
        PF_DLI
        PF_ECMA
        PF_GOSIP
        PF_HYLINK
        PF_IMPLINK
        PF_INET
        PF_INET6
        PF_ISO
        PF_KEY
        PF_LAST
        PF_LAT
        PF_LINK
        PF_MAX
        PF_NBS
        PF_NIT
        PF_NS
        PF_OSI
        PF_OSINET
        PF_PUP
        PF_ROUTE
        PF_SNA
        PF_UNIX
        PF_UNSPEC
        PF_USER
        PF_WAN
        PF_X25
        SCM_CONNECT
        SCM_CREDENTIALS
        SCM_CREDS
        SCM_RIGHTS
        SCM_TIMESTAMP
        SHUT_RD
        SHUT_RDWR
        SHUT_WR
        SOCK_DGRAM
        SOCK_RAW
        SOCK_RDM
        SOCK_SEQPACKET
        SOCK_STREAM
        SOL_SOCKET
        SOMAXCONN
        SO_ACCEPTCONN
        SO_ATTACH_FILTER
        SO_BACKLOG
        SO_BROADCAST
        SO_CHAMELEON
        SO_DEBUG
        SO_DETACH_FILTER
        SO_DGRAM_ERRIND
        SO_DONTLINGER
        SO_DONTROUTE
        SO_ERROR
        SO_FAMILY
        SO_KEEPALIVE
        SO_LINGER
        SO_OOBINLINE
        SO_PASSCRED
        SO_PASSIFNAME
        SO_PEERCRED
        SO_PROTOCOL
        SO_PROTOTYPE
        SO_RCVBUF
        SO_RCVLOWAT
        SO_RCVTIMEO
        SO_REUSEADDR
        SO_REUSEPORT
        SO_SECURITY_AUTHENTICATION
        SO_SECURITY_ENCRYPTION_NETWORK
        SO_SECURITY_ENCRYPTION_TRANSPORT
        SO_SNDBUF
        SO_SNDLOWAT
        SO_SNDTIMEO
        SO_STATE
        SO_TYPE
        SO_USELOOPBACK
        SO_XOPEN
        SO_XSE
        UIO_MAXIOV
);

@EXPORT_OK = qw(CR LF CRLF $CR $LF $CRLF

               IPPROTO_TCP
               TCP_KEEPALIVE
               TCP_MAXRT
               TCP_MAXSEG
               TCP_NODELAY
               TCP_STDURG);

%EXPORT_TAGS = (
    crlf    => [qw(CR LF CRLF $CR $LF $CRLF)],
    all     => [@EXPORT, @EXPORT_OK],
);

BEGIN {
    sub CR   () {"\015"}
    sub LF   () {"\012"}
    sub CRLF () {"\015\012"}
}

*CR   = \CR();
*LF   = \LF();
*CRLF = \CRLF();

sub sockaddr_in {
    if (@_ == 6 && !wantarray) { # perl5.001m compat; use this && die
        my($af, $port, @quad) = @_;
        warnings::warn "6-ARG sockaddr_in call is deprecated"
            if warnings::enabled();
        pack_sockaddr_in($port, inet_aton(join('.', @quad)));
    } elsif (wantarray) {
        croak "usage:   (port,iaddr) = sockaddr_in(sin_sv)" unless @_ == 1;
        unpack_sockaddr_in(@_);
    } else {
        croak "usage:   sin_sv = sockaddr_in(port,iaddr))" unless @_ == 2;
        pack_sockaddr_in(@_);
    }
}

sub sockaddr_un {
    if (wantarray) {
        croak "usage:   (filename) = sockaddr_un(sun_sv)" unless @_ == 1;
        unpack_sockaddr_un(@_);
    } else {
        croak "usage:   sun_sv = sockaddr_un(filename)" unless @_ == 1;
        pack_sockaddr_un(@_);
    }
}

sub AUTOLOAD {
    my($constname);
    ($constname = $AUTOLOAD) =~ s/.*:://;
    croak "&Socket::constant not defined" if $constname eq 'constant';
    my ($error, $val) = constant($constname);
    if ($error) {
        croak $error;
    }
    *$AUTOLOAD = sub { $val };
    goto &$AUTOLOAD;
}

XSLoader::load 'Socket', $VERSION;

1;

response 10 of 11:

Oct 30 04:38 UTC 2006

According to the ``perlfunc'' man page, gethostbyname() is a perl builtin
function.