appb_05.htm

来自「by Randal L. Schwartz and Tom Phoenix I」· HTM 代码 · 共 328 行 · 第 1/2 页

die "Couldn't get the size of the image"
  unless defined $fred_height;</pre></blockquote>

</div>
<a name="lperl3-APP-B-SECT-5.8" /><div class="sect2">
<h3 class="sect2">B.5.8. The Net::SMTP Module</h3>

<p>If you want your program to be able to send
<a name="INDEX-1176" />email through an
<a name="INDEX-1177" />SMTP server (which is the way most of
us send email these days, whether you knew that or not), you may use
the <tt class="literal">Net::SMTP</tt><a name="INDEX-1178" /> module to do the work.<a href="#FOOTNOTE-405">[405]</a> This module, which is
available from CPAN, is object-oriented, but you may simply follow
the syntax to use it. You will need to change the name of your SMTP
host and the other items to make this work on your system. Your
system administrator or local expert can tell you what to use. For
example:
</p><blockquote class="footnote">
<a name="FOOTNOTE-405" /><p>[405]Yes, this means that you are now able to use Perl to send spam.
Please don't. </p> </blockquote>

<blockquote><pre class="code">use Net::SMTP;

my $from = 'YOUR_ADDRESS_GOES_HERE';         # maybe [e-mail]
my $site = 'YOUR_SITE_NAME_GOES_HERE';       # maybe bedrock.edu
my $smtp_host = 'YOUR_SMTP_HOST_GOES_HERE';  # maybe mail or mailhost
my $to = '[e-mail]';

my $smtp = Net::SMTP-&gt;new($smtp_host, Hello =&gt; $site);

$smtp-&gt;mail($from);
$smtp-&gt;to($to);
$smtp-&gt;data( );

$smtp-&gt;datasend("To: $to\n");
$smtp-&gt;datasend("Subject: A message from my Perl program.\n");
$smtp-&gt;datasend("\n");
$smtp-&gt;datasend("This is just to let you know,\n");
$smtp-&gt;datasend("I don't care what those other people say about you,\n");
$smtp-&gt;datasend("I still think you're doing a great job.\n");
$smtp-&gt;datasend("\n");
$smtp-&gt;datasend("Have you considered enacting a law naming Perl \n");
$smtp-&gt;datasend("the national programming language?\n");

$smtp-&gt;dataend( );                             # Not datasend!
$smtp-&gt;quit;</pre></blockquote>

</div>
<a name="lperl3-APP-B-SECT-5.9" /><div class="sect2">
<h3 class="sect2">B.5.9. The POSIX Module</h3>

<p>If you need access to the POSIX (IEEE Std 1003.1) functions, the
<tt class="literal">POSIX</tt><a name="INDEX-1179" /> module is for you. It provides many
functions that C programmers may be used to, such as trigonometric
functions (<tt class="literal">asin</tt>, <tt class="literal">cosh</tt>), general
mathematical functions (<tt class="literal">floor</tt>,
<tt class="literal">frexp</tt>), character-identification functions
(<tt class="literal">isupper</tt>, <tt class="literal">isalpha</tt>), low-level
IO functions (<tt class="literal">creat</tt>, <tt class="literal">open</tt>), and
some others (<tt class="literal">asctime</tt>, <tt class="literal">clock</tt>).
You'll probably want to call each of these with its
"full" name; that is, with <tt class="literal">POSIX</tt> and a
pair of colons as a prefix to the function's name:
</p>

<blockquote><pre class="code">use POSIX;

print "Please enter a number: ";
chomp(my $str = &lt;STDIN&gt;);

$! = 0;  # Clear out the error indicator
my($num, $leftover) = POSIX::strtod($str);

if ($str eq '') {
  print "That string was empty!\n";
} elsif ($leftover) {
  my $remainder = substr $str, -$leftover;
  print "The string '$remainder' was left after the number $num.\n";
} elsif ($!) {
  print "The conversion function complained: $!\n";
} else {
  print "The seemingly-valid number was $num.\n";
}</pre></blockquote>

</div>
<a name="lperl3-APP-B-SECT-5.10" /><div class="sect2">
<h3 class="sect2">B.5.10. The Sys::Hostname Module</h3>

<p>The
<tt class="literal">Sys::Hostname</tt><a name="INDEX-1180" /> module provides the
<tt class="literal">hostname</tt><a name="INDEX-1181" /> function, which will be the network
name of your machine, if that can be determined. (If it can't
be determined, perhaps because your machine is not on the Internet or
not properly configured, the function will die automatically;
there's no point in using <tt class="literal">or die</tt> here.) For
example:
</p>

<blockquote><pre class="code">use Sys::Hostname;
my $host = hostname;
print "This machine is known as '$host'.\n";</pre></blockquote>

</div>
<a name="lperl3-APP-B-SECT-5.11" /><div class="sect2">
<h3 class="sect2">B.5.11. The Text::Wrap Module</h3>

<p>The <tt class="literal">Text::Wrap</tt><a name="INDEX-1182" />
<a name="INDEX-1183" /> module supplies the
<tt class="literal">wrap</tt><a name="INDEX-1184" /> function, which lets you implement
simple <a name="INDEX-1185" />word-wrapping. The first
two parameters specify the indentation of the first line and the
others, respectively; the remaining parameters make up the
paragraph's text:
</p>

<blockquote><pre class="code">use Text::Wrap;

my $message = "This is some sample text which may be longer " .
  "than the width of your output device, so it needs to " .
  "be wrapped to fit properly as a paragraph. ";
$message x= 5;

print wrap("\t", "", "$message\n");</pre></blockquote>

</div>
<a name="lperl3-APP-B-SECT-5.12" /><div class="sect2">
<h3 class="sect2">B.5.12. The Time::Local Module</h3>

<p><a name="INDEX-1186" />If you have a time (for example, from the
<tt class="literal">time</tt> function) that needs to be converted to a
list of year, month, day, hour, minute, and second values, you can do
that with Perl's built-in <tt class="literal">localtime</tt> function
in a list context.<a href="#FOOTNOTE-406">[406]</a> (In
a scalar context, that gives a nicely formatted string representing
the time, which is more often what you'd want.) But if you need
to go in the other direction, you may use the
<tt class="literal">timelocal</tt><a name="INDEX-1187" /> function from the
<tt class="literal">Time::Local</tt> module instead. It's important
to note that the value of <tt class="literal">$mon</tt> and
<tt class="literal">$year</tt> for January 2004 are not
<tt class="literal">1</tt> and <tt class="literal">2004</tt> as you might expect,
so be sure to read the documentation before you use this module. For
example:
</p><blockquote class="footnote"> <a name="FOOTNOTE-406" /><p>[406]The actual return value of
<tt class="literal">localtime</tt> in a list context is a little different
than you might expect; see the documentation.</p> </blockquote>

<a name="INDEX-1188" /><blockquote><pre class="code">use Time::Local;

my $time = timelocal($sec, $min, $hr, $day, $mon, $year);</pre></blockquote>

</div>


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