Diff: perlipc(1) - Waikato Linux Users Group

Differences between version 2 and predecessor to the previous major change of perlipc(1).

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Newer page:	version 2	Last edited on Tuesday, June 4, 2002 12:22:36 am	by perry	Revert
Older page:	version 1	Last edited on Tuesday, June 4, 2002 12:22:36 am	by perry	Revert

@@ -399,9 +399,9 @@

Here's an example of using ''open2()'':

- use FileHandle;

+ use ! FileHandle;

use IPC::Open2;

$pid = open2(*Reader, *Writer,

The problem with this is that Unix buffering is really going to ruin your day. Even though your Writer filehandle is auto-flushed, and the process on the other end will get your data in a timely manner, you can't usually do anything to force it to give it back to you in a similarly quick fashion. In this case, we could, because we gave ''cat'' a __-u__ flag to make it unbuffered. But very few Unix commands are designed to operate over pipes, so this seldom works unless you yourself wrote the program on the other end of the double-ended pipe.

@@ -468,9 +468,9 @@

!!Sockets: Client/Server Communication

While not limited to Unix-derived operating systems (e.g.,

-WinSock on PCs provides socket support, as do some

+! WinSock on PCs provides socket support, as do some

VMS libraries), you may not have sockets on

your system, in which case this section probably isn't going

to do you much good. With sockets, you can do both virtual

circuits (i.e., TCP streams) and datagrams

@@ -770,9 +770,9 @@

UDP protocol can be used to make a datagram

socket, used for message-passing.

-PeerAddr

+! PeerAddr

This is the name or Internet address of the remote host the

server is running on. We could have specified a longer name

@@ -785,9 +785,9 @@

, if you'd rather use

that.

-PeerPort

+! PeerPort

This is the service name or port number we'd like to connect

to. We could have gotten away with using just

@@ -831,9 +831,9 @@

#!/usr/bin/perl -w

use IO::Socket;

unless (@ARGV

-The web server handing the ``http'' service, which is assumed to be at its standard port, number 80. If the web server you're trying to connect to is at a different port (like 1080 or 8080), you should specify as the named-parameter pair, PeerPort =. The autoflush method is used on the socket because otherwise the system would buffer up the output we sent it. (If you're on a Mac, you'll also need to change every in your code that sends data over the network to be a instead.)

+The web server handing the ``http'' service, which is assumed to be at its standard port, number 80. If the web server you're trying to connect to is at a different port (like 1080 or 8080), you should specify as the named-parameter pair, ! PeerPort =. The autoflush method is used on the socket because otherwise the system would buffer up the output we sent it. (If you're on a Mac, you'll also need to change every in your code that sends data over the network to be a instead.)

Connecting to the server is only the first part of the

process: once you have the connection, you have to use the

@@ -947,12 +947,12 @@

This is which protocol to use. Like our clients, we'll still

specify here.

-LocalPort

+! LocalPort

-We specify a local port in the LocalPort argument,

+We specify a local port in the ! LocalPort argument,

which we didn't do for the client. This is service name or

port number for which you want to be the server. (Under

Unix, ports under 1024 are restricted to the superuser.) In

our sample, we'll use port 9000, but you can use any port

@@ -1220,6 +1220,6 @@

CGI programming, DCE ,

FTP , IPC ,

NNTP , Proxy, Ptty, RPC ,

SNMP , SMTP , Telnet, Threads,

-and ToolTalk--just to name a few.

+and ! ToolTalk--just to name a few.

----