Learning Perl, 2nd edition
by Randal Schwartz and Tom Christiansen

Unconfirmed error reports are from readers. They have not yet been 
approved or disproved by the author or editor and represent solely 
the opinion of the reader.

This page was updated October 22, 2002.

Here's a key to the markup:

        [page-number]: serious technical mistake
        {page-number}: minor technical mistake
        <page-number>: important language/formatting problem
        (page-number): language change or minor formatting problem
        ?page-number?: reader question or request for clarification


UNCONFIRMED errors and comments from readers:


(15)  6th paragraph (not counting the code fragment):
The scalar variable name $someguess has been hyphenated at the end of the line
as $some-guess.


?16?
This line is confusing:
	
	[... insert definition of good_word() here ...]

It sounds like it is supposed to go inside of the [ ].

Also, it might be clearer for a beginner to say:
	
     	[... insert definition of good_word() from previous page here ...]


{18} 4th line of code (and several other places in the chapter where this 
piece of code is repeated):

Shouldn't "$words" read "%words"? Compare with line 8 on page 19.


{18} 4th  paragraph begins:
"The while loop reads lines from the wordslist file (via the WORDSLIST 
file-handle) one line at a time.  Each line is stored in the $name variable."

THIS IS NOT QUITE RIGHT.... as the storing is alternated first to $name,
then $word.  See the code above and the explanation after which correctly
states the process.

So you might say "Each line is stored alternately, first to $name variable
via ($name = <WORDSLIST>), then to $word variable via $word = <WORDSLIST>;"


{18} reads:
        
	The while loop reads lines from the wordslist file (via 
	the WORDSLIST file handle) one line at a time.    

should read:
        
	The while statement reads lines from the wordslist file
	(via the WORDSLIST file handle) a line at a time.    

Note: The whole loop brings in two lines from the wordslist file, assuming it 
isn't the end of the file, once in the while statement and another at $word = 
<WORDSLIST>.


{22} We're looping through a set of code to get information from every .secret
file in our main directory with this:

	while ( defined($filename = glob("*.secret")) )

Then in "The Final Programs," this syntax is changed to

	while ($filename = <<*.secret>)

without explanation.  

From booktech: It is possible to use file name globbing within angle
brackets, so

	while ( defined($filename = glob("*.secret")) )

and

	while ($filename = <*.secret>)

are essentially the same thing.  Basically the angle bracket method is older.
It won't work with variables.

	$foo = '*.secret';
	@fnames = <$foo>;

won't work, but

	$foo = '*.secret';
	@fnames = glob($foo);

will work.


(22)  4th line from the bottom in the code section:
I think it should be: 
   
	if (-M WORDLIST < 7.0 ) {

instead of 
   
	if (-M WORDLIST >= 7.0 ) {

The same mistake happened in page23, 24, 26 in the code section.


?27? first paragraph, *.dir and *.pag: 
I ended up with a single database file of *.db that the "file" command shows 
as a Berkely DB hash file. I am using Perl on Redhat Linux, kernel 2.0.?


{27} footnote:
It says, "The actual permissions of the files will be the logical AND of 0666 
and your process's current umask."

I suppose that should be ".... _bitwise_ AND of 0666 and _the bitwise NOT of_ 
your process's current umask."   At least, that's how creat(2) does it: (mode 
& ~umask).


{28} "say hello" program, line 6: 
The truncation and lower-casing of the name should be done here instead of in 
good_word, so that lastdb won't contain multiple entries for equivalent names.


(28)  2nd line in the code of final program:
I think it should be:
    
	init_words();

instead of:
    
	&init_words(); 


{24}  very top:
On the very top of page 24 (or on the very bottom of page 23) the line:
	
	while ($name = <WORDSLIST>) {

is missing from the source listing.


{29} line 26-28 (mid of page, function good_word {} ):
The code in these three lines (starting "if ($somename eq "randal")") will 
never be reached, that has been already excluded in line 6 of this code 
(starting on page 28: "if ($name =~ /^randal\b/i))."


{33} In the 5/99 reprint, changing "double-quoted" back to  "single-quoted" 
doesn't handle 'hello\n' which prints as hello\n not hello<CR>

In fact, 'hello\\n' results in hello\n, which is exactly the same result. So 
it is not necessary to "precede the backslash by a backslash" for 
single-quoted strings. Removing that sentence would help, but also the 
parenthetical statement on pp 34 top is in question, because, as you can see, 
preceding a backslash by a backslash within single quotes apparently doesn't 
have special meaning, despite what even perldata says.


[40] 1st paragraph:
Shouldnt the -w option of Perl catch the following error:

	#!/usr/bin/perl -w
	$result = " 123.45fred" + 10;
	print "result is $result";

	i97-dev(tbryant) # perl sample2.perl
	result is 133.45i97-dev(tbryant) #   


(41) paragraph 1, line 1: 
"operation" should be "operation (aside from dereferencing)". In Perl, 
dereferencing is implicit, which makes it easy to overlook.


(48) Literal Representation: 
Calling lists containing variables or expressions "literals" is a misnomer.

{48} 1st code, line 1:
"array" should read "list" (it's not yet an array).


{49} 2nd code block, 2nd line:

	(1.2 .. 5.2)	# Same as (1.2, 2.2, 3.2, 4.2, 5.2)

It's actually the same as (1, 2, 3, 4, 5).


{49} 3rd code example: 
same error as above.


?49? Confusing: The comment at the end of the line of code says "three element
literal array" If it's meaning to refer the reader to the previous code that 
defines "@a", shouldn't it be *four* element?


{49} The third to last line reads:
   	
	print("The answer is ",$a,"\n); # three element literal array

The statement does not compile ("Use of uninitialized value at list line ...");
It should read:
   
	print("The answer is ",@a,"\n); # three element literal array


{49}  ninth line:
The use of the list constructor operator is described incorrectly.

	"This operator creates a list of values starting at the left scaler
	value up through the right scaler value, incrementing by one each
	time." 

Should read 

	"This operator craetes a list of values starting at the integer 
	value of the left scaler value up through the integer
	value of the right scaler value, incrementing by one each time."

The example of 

	(1.2 .. 5.2)  #same as (1.2, 2.2, 3.2, 4.2, 5.2)

should be      

	(1.2 .. 5.2)  #same as (1, 2, 3, 4, 5,)

I have tried this on PERL ver 4.018 PL 36 under Slackware ver 2.3 and on PERL 
ver 5.005.03 on a server at school.


?52? When introducing slices, you might consider throwing in an example where 
the array subscripts are random, instead of consecutive, ascending values... 
unless Perl requires consecutive, ascending values (which I kind of doubt).


{52}  near the bottom of the page:
Example says:

	@fred[1,2] = (9,10); # change the last two values to 9 and 10

The wording "the last two values" only applies for the special case where 
@fred has only three values.  You could instead say, without loss of 
generality, "change the second and third values to 9 and 10 respectively".


{53} examples at top, last line: 
No slice here.


?53?: From the middle to the bottom, talking about subscripts, you've got 
conflicting and wrong information.

	"If you access an array element beyond the ends of the current
	array (that is, an index of less than zero or greater than the last
	element's index), the undef value is returned without warning."

Not true of negative subscripts, as later 

	"A negative subscript on an array counts back from the end."

	"Assignment to an array element with a subscript of less than zero
	is a fatal error.."

Not true, it is the same as referencing a negative subscript, it counts from 
the end.


{55}  1st indented example paragraph:
Example says:

	@y = sort(@y); # @y gets 1,16,2,32,4,64,8

This should read:

	@y = sort(@y); # @y gets (1,16,2,32,4,64,8)

Similarly, the line two lines up should read:

        # @x gets ("large","medium","small")


?67? "Notice once again that accessing an element of a hash requires different
punctuation than when you access the entire hash".  Make the link back to the 
arrays section (where @ becoming $ was explained in depth) more clear.


{68} Now reads: 

	if (keys(%somehash)){ # if keys() not zero:
      	   ...; #array is non empty

It is better to write as 

  	if (keys(%somehash)){ # if keys() not zero:
                      	    #array is non empty
           ...;

Since "#array is non empty" is also a part of comment of "if 
(keys(%somehash))", but not "...". It will be consistent with the style of the
book.


{70} under Hash Slices:

	%league{keys %score} = values %score

should be 

	@league{keys %score} = values %score


(70)  Under Topic of "Hash Slices":
Two or three more sentences clarifying why the use of @ in 
	
	print "scores are: @score{@players}\n";

rather than using
	
	print "scores are: %score{@players}\n";

The use of @ rather than % when referring to a hash here is worthy of more 
explanation.  Fortunately there is room for it.


{78} Line -7 reads: 

	"or put it as the first character within the list". 

So if we want find a line containing any "]" or an "a", we can use /[]a]/, but
it does not work.

If we put a backslash, then it is OK. It also works for [. (At first I think [
and ] are treated differently in perl.)


{81} Now reads:

	"In this case , making that match lazy  (with a trailing to "?") 
	will actually simplify the work that Perl has to perform, so you 
	may want to consider that".
 
In fact I think ? will do the forward tracking. Therefore 

	$_ = "a xxx ce xxxxci ,,,cd" 
	/a.*?ci.*d/ 

will also match.  It is not true that "the a.*?c now matches the fesest 
characters between the a and c."

The difference between ? and no ? is not only in speed, but some other place 
as well, see the following example

	$_= "a xxx c xxxxxxx c xxx d";";
	s/c.*d/KK="a xxx c xxxxxxx KK"
	s/c.*?/KK="a xxx KK"


[83] 3rd para. from bottom: 
This para. states that the caret has special meaning only when "it makes sense
to match the beginning of the string."  However, Tom Phoenix had this to say:

In general, any caret in a regular expression is special and will need to be 
escaped. To match caret at the beginning of the line, then, /^\^/ will work.


{83} \b and \B are different for letters and some symbols, as indicated in the
text: /\b\+\b/ matches "x+y" but not "++" or " + ". This is as the same as 
-,*,/,=,++, Notice that + and * have different meaning if there is no \ 
before. I guess \ before the symbol changes b to B and vice versa. I suggest  
to say that "Notice the usage of /,+,*, if we want to search these symbols 
themselves, we have to put backslash before them, However it will change the 
meaning of \b and \B."


{84} Table 7-2, Sequence and anchoring: 
Add \b and \B.


{84} In the comment of "(a|b)(c|d)", it is better to add "same as [ab][cd]."


(85) Now reads: 

	"In this case, <STDIN> yields the next line". 

It is better to say "the first <STDIN>". Also it looks bad from a politeness 
aspect, because we don't care what is the second input and just say "sorry". 
If so, why should we ask for the second input?


(85) first code block, 3rd line:
The example goes
  
	$a =~ /(.)\l/;     # also true ....

I would assume that should be the digit "1," not the letter "l"...Same for 
next line.


(88) In line -1: 
It is better to say "Here the last g makes four matches, every time set a new 
value for $1, in turns to be "this", "is", "a", and "test"". (Recall "If you 
want the replacement to operate on all possible matches instead of just the 
first match".)


(90) Middle, "The join function takes a list of values ...":

     	$bigstring = join(@glue, @list);

Readers will think the "list" in the first line is just the @list in the 
second line. Actually in the second line it should be a list of scalar values 
or arrays, such as 

     	$bigstring = join(@glue, $var1,@list1,$var2, ...);

And there are two formats, (put "join" in parenthsis or not).


{91}  Exercise 2.a.:
The answer suggested by the authors to this exercise uses the && operator, 
which is not introduced in the text until p. 106. 


(94)  sub gimme_a_or_b towards the bottom:
It says "returns $a" when it should be "return $a."


{97} line 18: 
"@result;" should be "return @result;"


{97} In the first paragraph after second code block: 
The last underscore in "@_[1..$#_]" may be incorrect.


{105} line -5: 
"From." should be "From: ", i.e., that in line -7.


(105) Now reads:
	
	This set of statements tries all successive values of 
	two small numbers multiplied together until it finds a 
	pair whose product is 63 (7 and 9). 

Should read:

	This set of statements tries all successive values of 
	two small numbers multiplied together until it finds a 
	pair whose product is 63 (9 and 7). 


{113} Table 10-1, -x and -X: 
should start "File is executable or directory is searchable"


(115) line 13:
"stat" should use Constant Width font.


(125) 2nd section: 
It says:

	... in Chapter 6, Basic I/O, I mentioned that print and 
	print STDOUT were identical, because STDOUT was the default 
	for print ....

however, it was in Chapter 10, page 111.


{126} Changing the Format Name, line 3: 
"to" should be "in".


[130] bottom while example:
On page 86, it shows that you need to put an "m" in front of the new delimiter:

	m#^/usr/etc#

But in the example on page 130:

	while ( $nextname = </etc/host*>) {
   	   $nextname =~ s#.*/##;
  	  print "... $nextname\n";
	}

It took me awhile to figure out why this was working and what did I miss with 
the syntacts of the # symbol. I didn't read anywhere, even after the example, 
that this was even using the # as the new delimiter.


{133} There's a minor error in the comment in line 3 of the code sample:

	print "$name\n";  # prints ., .., passwd, group, and so on

should read

	print "$name\n";  # prints ., .., group, passwd, and so on

because the list has been sorted.


(133) Now reads:

	On the other hand, it is like the shell's echo*.

Should read:

	On the other hand, it is like the shell's echo *.


{137} Creating Hard and Soft Links: paragraph 2, line 1: 
Swap "to" and "from"; link example, line 2: "fred to bigdumbguy" should be 
"bigdumbguy to fred"; last paragraph, line 2: swap "to" and "from".


{138} symlink example, line 2: 
"neighbor" should be "barney"


?138? line -1: 
What does "Fred" mean? should it be "gravelpit"?


(138) paragraph 5, line 2: 
Delete "comparable".


{139} Middle: 
Should "for user" be "for owner"? Also, here the definiton of "owner" and 
"group" appears (in section Modifying Ownership) after they are used (in 
section Modifying Permissions), it seems not suitable.


{140} second paragraph of "Modifying Timestamps", last sentence:
Actually, the time value of UNIX does not overflow in the year 2000, but on 
Tuesday, January 19, 2038 at 03:14:08 UTC. (Source: David A. Curry: UNIX 
Systems Programming for SVR 4, O'Reilly & Associates 1996, p. 171.)


{143}, I'm pretty sure it should say:

  system("date >right_now") || die "cannot create right_now";

rather than:

  system("date >right_now") && die "cannot create right_now";
                            ^^

{144} line -12: 
Should "angle brackets" be "single quotes"?


?146? Shouldn't you have something in "Using Processes as Filehandles" about 
checking the return status of the open(). It is different from the "open() or 
die" of regular files.


{148} para. 2, line 3: 
"shell" should be "shell command".


{150}  4th paragraph:
Paragraph 4, sentence 2: "A signal is a one-bit message..."

If the signals are numbered with small numbers like 15 or 31, as noted later 
in the same paragraph, perhaps this should read "A signal is a one-byte 
message..."

Or perhaps I'm being far too literal.


{151} last example, line 3: 
"huge_array" should be "huge_list".


{151} Middle, $SIG{'INT'}: 
In page 68, hash function, usually we use double quotes for keys, here we use 
single quotes. It is better to  say something in page 68, like "we can also 
use single quotes".


{155} 2nd and 3rd paragraphs:
The 3rd paragraph states that substr will default the starting position to 0 
if the starting position argument is a negative number larger than the length 
of the string. That's not true; substr behaves as if it created a temporary 
string and prepended null characters whose number equals the "excess" length. 
Examples:

	print(substr("abc",-5,1)."\n"); # prints nothing
	print(substr("abc",-5,2)."\n"); # prints nothing
	print(substr("abc",-5,3)."\n"); # prints a

The 2nd paragraph makes reference to an "ending position", but there is no 
ending position in the syntax for substr.


?158? Last paragraph: 
This paragraph tells us we can sort stringe numerically, and if two strings 
are numerically equal, sort them by ASCII. That is right from the logic 
aspect. However if we consider the reality, how could two strings are 
numerically equal but not the same?


{161} line -11: 

	"def became abc and ghi becomes a signle d". 

It is right. But it will give readers the impression that tr is a command for 
string replacement (def became abc) and in fact, tr is a command for character
replacement.


{164} 1/3 down page: 
"/etc/passwd line split apart" should be "/array/list line split apart" and 
"an array" should be "a list">


{164} The examples given are:

	$idnum = getpwuid ("daemon");
	$login = getpwnam (25);

This should be:

	$idnum = getpwnam("daemon");
	$login = getpwuid(25);

Which means the sentence "They each return the thing you've asked them to get"
seems incorrect as well.  They really return the other thing. Getting the 
login name returns the ID, getting the ID returns the login name.

>From perldoc -f getpwuid:

"In scalar context, you get the name, unless the function was a lookup by 
name, in which case you get the other thing, whatever it is. (If the entry 
doesn't exist you get the undefined value.) For example:

    	$uid   = getpwnam($name);
    	$name  = getpwuid($num);
"

Running the examples seems to bear this out.  


{166} paragraph 1, line 1: 
"string value" should be "the string value of their home directory."


{167} 1/3 down page: 

	"either ABCD or DCBA, depending on [endian]"

I don't have a little-endian to test, but I though it should be "CDAB".


{170} paragraph 3, line 3: 
"array" should be "hash"; paragraph 4, line 2: "array" should be "hash".


{171} Opening and Closing DBM Hashes: paragraph 1, line 1: 
"array" should be "hash"; example 1: ARRAYNAME should be HASHNAME; paragraph
2, line 1: ARRAYNAME should be HASHNAME; example 2, comment: Should be "open 
mydatabase into %FRED."


{171} line -8: 
"DBM array" should be "DBM hash".


?173? line 12-14: 
Here >,<,>> are all for read/write, so what is the difference?


{175} paragraph 3, line 3: 
"after" should be "before".


?183? line 8: 
This URL is corresponding to screen in page 191, so do we need to put one more
name=value pair such as "name=someone's name"?


?186?  There isn't an index entry for "use" or the qw operator. It needs more 
explanation other than "we'll employ the qw() notation; this way it will be 
easier to expand the list later."


{186}  code example"
After END_of_Start, there is a useless my in :

	my $favorite = param("flavor:);

It should read :

	$favorite = param("flavor");

The added "my" bugs the code.


{188} In the HTML code on the form input is given as

	What's your flavor? <INPUT NAME="favorite" VALUE="mint">

The problem is that the CGI script it should talk to (ice_cream, version 2, p.
187) expects input of the form "...?flavor=mint", not "...?favorite=mint".  
In order for these two to interface properly, the input line in the form 
should be 

	What's your flavor? <INPUT NAME="flavor" VALUE="mint">


?190? The "use strict" line is never explained except in a brief comment after
a pound sign.  Anyone who attempts to use it without adding the "my" operator 
to variables is going to get a rude surprise. It needs a brief but more 
thorough explanation (and should be in the index) as to why it's being used.


(191) Now reads:
    
	   my $flavor = param("flavor"); my $scoops = param("scoops");
 	my $taxrate = 1.0743;
 	my $cost = sprintf("%.2f", $taxrate * (1.00 + $scoops * 0.25));
 	print p("Ok, $who, have $scoops scoops of $flavor for \$$cost.");

Should read:
    
	my $flavor = param("flavor"); my $scoops = param("scoops");
    	my $taxrate = 1.0743;
    	my $cost = sprintf("%.2f", $taxrate * (1.00 + $scoops * 0.25));
    	print p("Ok, $who, have $scoops scoops of $flavor for \$$cost.");


{193} line 7, "To add a scrolling list to a form, here's all you need to do":

But actually, you are talking about the previous example: Ice Cream Stand. 
Therefore I suggest to change it to:

If instread of popup_menu flavor, we want to use scrolling_list(), we can 
replace the corresponding line with the following code.

print p("What flavor: ", scrolling_list(
		     -NAME => "flavor",
		     -VALUES => [ qw(mint chocolate cherry vanilla peach) ],
		     -LABELS => {
			 mint => "Mighty Mint",
			 chocolate => "cherished chocolate",
			 cherry => "Cheery Cherry",
			 vanilla => "Very Vanila",
			 peach => "Perfectly Peachy",
		     },
		     -SIZE => 3,
		     -MULTIPLE => 'true',
		     ));

And notice that it is better to change "flavors" to "flavor" in the NAME row.


?193-4?  The book doesn't have an index entry for the "=>" operator, which is 
used in the CGI chapter and is never explained (as far as I can tell) in that 
chapter or the chapter on hashes.


{195} 2nd code, third line: 
You use bail here, but bail isn't mentioned or described so far (it is 
described much later in the book).


(195) I wanted to look at the script example for a guestbook in "Learning
Perl, 2nd ed." When I get to the use of the "flock" and "bail" functions on 
page 195, I think, "I wonder if these were more thoroughly explained earlier 
in the book..." So I go to the index, but neither function is there. It would
seem that if there were any sort of consistent criteria for index keywords, it
would be that all functions (that were utilized in the book) would be 
included. I do get a chuckle out of the "Scooby Doo" joke, but it's not worth 
the frustration of knowing that I can't rely on the index to get me where I 
need to go.  So I go to the other Perl book on my desk, "Perl in a Nutshell," 
which does, unlike many of your books, tout itself as "A Desktop Quick 
Reference." The "flock" function is there, but no "bail."

As it stands, I could just copy the script, get a functional guestbook, and 
not know what the hell any of it meant. That's not what I want, though, and 
that's not why I buy books from you guys.


(198) Now reads:
    
	   $cur->param("date", scalar localtime); # set to the current time
 	@entries = ($cur);                        # save message to array

Should read:
    
	$cur->param("date", scalar localtime); # set to the current time
    	@entries = ($cur);                        # save message to array


{204} bullet 3, line 1: 
"executable" should be "searchable".


{207} Now reads:
    
	if ($webdoc->is_success) { # found it
    	print STDOUT "$url: ", $webdoc->title, "\n";
    	} else { # something went wrong    
    	print STDERR "$0: Couldn't fetch $url\n";

Should read:
    
	if ($webdoc->is_success) { # found it
             print STDOUT "$url: ", $webdoc->title, "\n";
    	} else { # something went wrong    
             print STDERR "$0: Couldn't fetch $url\n";


{213} line 2 of #3: 
The printed string should end with a newline instead of a blank.

{213} answer to number 3:  
You need to integerize the random number with int(rand(@b)).


{216} Program listing and describing text don't suit each other, maybe there 
is a bit 1st edition and a bit 2nd edition.  We think that the end of the 
first para (after the program listing) and the beginning of 2nd para are not 
right any longer. 


[218] Answer 1-e:
Answer section says that /(^|\s)(\S+)(\s+\2)+(\s|$)/ will match the same word 
written two or more times in a row. I have copied my script below; perl 
-version reports 5.005_03 for sun4-solaris; I'm running Solaris 2.7 on a 
SparcStation 2. When I run this script and input something like "word\n" then 
"no match!" is output. If I enter "word word<CR>" then "it matches!" is 
output. However, if I enter something like "word again<CR>" then "it matches!"
is output which means that the expression is looking for two words, but they 
do not have to be the same word. I think that the answer given in the back of 
the book is in error, and if possible I would like to know how to solve this 
problem correctly. Also, the answer given for exercise 7-1b does not seem to 
work either, when used in place of the regular expression in the code below...
the problem with 7-1b is that the expression matches anything, which is not 
very instructive. 

#!/usr/bin/perl -w
#
#	This program will construct a regular expression that matches
#	the same word written two or more times in a row(with possibly
#	varying intervening whitespace), where "word" is defined as a
#	nonempty sequence of nonwhitespace characters.
#

while(<>) {
	if(/(^|\s)(\S+)(\s+\2)+(\s|$)/) {
		print "it matches!\n";
	} else {
		print "no match!\n";
	}
}


{219} Now reads:
    
	print if
            (/^[^aeiou]*a[^eiou]*e[^aiou]*i[^aeou]*o[^aeiu]*u[^aeio]*$ );

Should read:
    
	print if
            (/^[^aeiou]*a[^eiou]*e[^aiou]*i[^aeou]*o[^aeiu]*u[^aeio]*$/i );


{219} The answer for Chapter 7 2c doesn't correctly find words with "aeiou" 
and in that order. The errata on-line has a correction to permit mixed upper 
and lower case, but that string is still incorrect.

The correct string should read:

 	/^[^aeiou]*a[^aeiou]*e[^aeiou]*i[^aeiou]*o[^aeiou]*u[^aeiou]*$/i


{219} Exercise 7.2c:
The regular expression string for vowel matching doesn't have a terminating 
slash /.


[221]  Code block at top of page:

	"my($num) = @_;

When I typed in the entire example exactly, the return value of the subroutine
is always "one".

In my own solutionI used:

	"my($num) = $_[0]; (this works)

Is this example incorrect or am I doing something wrong?


{221} paragraph 2, line 3: 
"array element" should be "hash element."


[224] code sample for daytime socket client:
I cannot get the example to work. (Linux Mandrake 6.0).

I tried to work it through as follows:
As per perl's suggestion, I typed "h2ph * sys/*" in /usr/include. Then I got 
an error that stddef.ph could not be found. After finding it I figured out how
to add its directory to @INC. Now I am getting error messages that I cannot 
solve and I am stuck. Here is the output:

--------------------------------------------------
Prototype mismatch: sub main::__NFDBITS vs () at (eval 61) line 1.
Prototype mismatch: sub main::__FD_SETSIZE vs () at (eval 62) line 1.
String found where operator expected at (eval 199) line 1, near "&__const 'struct sockaddr'"
        (Missing operator before  'struct sockaddr'?)

------------
Here is the code (I commented out a lot to show that the error is early on in the code):
--------------------------------------------------
#!/usr/bin/perl
BEGIN { 
$dir ="/usr/lib/perl5/5.00503/i386-linux/linux";
unshift(@INC, $dir) 
}
# why does the following NOT work
#use lib $dirl;
#print $INC[0], "\n";
#print @INC , "\n";

require 'sys/socket.ph';
$sockaddr = 'S n a4 x8';
chop($hostname = `hostname`);
#($name, $aliases, $proto) = getprotobyname('tcp');
#($name, $aliases, $port) = getservbyname('daytime','tcp');
#($name, $aliases, $type, $len, $thisaddress) = gethostbyname($hostname);
#$thisport = pack($sockaddr, &AF_INET, 0, $thisaddr);
#$thatport = pack($sockaddr, &AF_INET, $port, $thisaddr);
#
#socket(S, &PF_INET, &SOCK_STREAM, $proto) ||
# die "cannot create socket\n";
#bind(S, $thisport) || die "cannot bind socket\n"; # optional
#connect(S, $thatport) || die "cannot connect socket\n";
#while (<S>) {
# print;
#}
#exit 0;


(226) #2, paragraph 2, line 1: 
"prompt" should be "prompt for."


{227} #3, last line of program, die message: 
Swap "new" and "old".


{230} #1: 
The if statement should begin

    	if ($slash == 0) {
           $head = "/";
           $tail = substr($_, 1);
    	} elsif ($slash > 0) {


(232) The page ends,

	Yes, this one needs some explaining.

But none appears. Also, there is no answer to question 2. Page(s) seem to be 
missing. 


{240} Table B-7 Mathematics: 
The first item in the module list should be "integer" with a small "i" - 
currently it's listed as Integer, which doesn't exist.


{246} A Simple Client: client code, next to last line: 
"or" should be ||.


{247} Now reads:
    	
	$remote = IO::Socket::INET->new( Proto => "tcp",
    	PeerAddr => $host,
    	PeerPort => "http(80)",
    	);

Should read:
    	
	$remote = IO::Socket::INET->new( Proto => "tcp",
             PeerAddr => $host,
             PeerPort => "http(80)",
    	);


{249} code, line 11: 
"or" should be ||.


(251) Full Interprocess Communications, paragraph 2: 
Delete.


INDEX:

(257) left column:
should include $@, page 253


(259) should include bail, 195.


(261) should include flock, 112, 195.


(264) Should include or, 246, 249.


(265) Missing entry in Index for qw() notation. It currently just gives page 
186; it should also give page 8.


{INDEX} It looks like the chop and chomp functions are indexed together under 
chop.  It would be nice to have a chomp index entry.

There are two operators, chomp() and chop().  Unfortunately, the index in 
Learning Perl doesn't have an entry for chomp() and further combines chomp() 
references with those of chop(), which is an incorrect assumption.

I also noted that the die() operator is listed in the index as having a first 
reference on page 23, when the actual first reference appears on page 19. It's
also curious that the book lists these elements as functions, for example, 
"die function" whereas the index lists the element as the "die() operator."

chop() is supposed to be chomp()


[271]  Answer to exercise 2, chap 6:
Question appears to ask for a program which prints the contents of files 
upside-down with lines flipped. That is, if two files are being read is being 
read, and they contain:

file #1:   whatever whenever
file #1:   antifignon something
file #2:   a few more words

The output would be:

	   gnihtemos nongifitna
	   revenehw revetahw
	   sdrow erom wef a

The answer given in the adendum, however, produces the following output (for 
the same input)

	   a few more words
	   antifignon something
	   whatever whenever


ON-LINE:
Near the end of E:\learn\ch05_05.htm, the line

	%league{keys %score} = values %score;

should have a leading "@" instead of "%".