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-rw-r--r--lang/perl5.12/files/patch-ac1096
1 files changed, 20 insertions, 1076 deletions
diff --git a/lang/perl5.12/files/patch-ac b/lang/perl5.12/files/patch-ac
index 451a47418899..633a25d8b940 100644
--- a/lang/perl5.12/files/patch-ac
+++ b/lang/perl5.12/files/patch-ac
@@ -1,1077 +1,21 @@
---- ./pod/perltrap.pod.orig Tue Jan 30 20:23:50 1996
-+++ ./pod/perltrap.pod Sun Jul 14 17:33:46 1996
-@@ -172,7 +172,7 @@
+--- hints/freebsd.sh.orig Thu Apr 24 01:01:37 1997
++++ hints/freebsd.sh Fri May 23 21:06:35 1997
+@@ -76,12 +76,18 @@
+ d_setreuid='define'
+ d_setegid='undef'
+ d_seteuid='undef'
++ d_dosuid='define'
+ ;;
+ #
+ # Guesses at what will be needed after 2.2
+ *) usevfork='true'
+ usemymalloc='n'
+ libswanted=`echo $libswanted | sed 's/ malloc / /'`
++ d_setregid='define'
++ d_setreuid='define'
++ d_setegid='undef'
++ d_seteuid='undef'
++ d_dosuid='define'
+ ;;
+ esac
- =item *
-
--printf() does not implement the "*" format for interpolating
-+C<printf()> does not implement the "*" format for interpolating
- field widths, but it's trivial to use interpolation of double-quoted
- strings to achieve the same effect.
-
-@@ -318,7 +318,7 @@
-
- =item *
-
--Use my() for local variables whenever you can get away with
-+Use C<my()> for local variables whenever you can get away with
- it (but see L<perlform> for where you can't).
- Using local() actually gives a local value to a global
- variable, which leaves you open to unforeseen side-effects
-@@ -332,75 +332,540 @@
-
- =back
-
--=head2 Perl4 Traps
-
--Penitent Perl 4 Programmers should take note of the following
--incompatible changes that occurred between release 4 and release 5:
-+=head2 Perl4 to Perl5 Traps
-+
-+Practicing Perl4 Programmers should take note of the following
-+Perl4-to-Perl5 specific traps.
-+
-+They're crudely ordered according to the following list:
-
- =over 4
-
--=item *
-+=item Discontinuance, Depracation, and BugFix traps
-
--C<@> now always interpolates an array in double-quotish strings. Some programs
--may now need to use backslash to protect any C<@> that shouldn't interpolate.
-+=item Parsing Traps
-
--=item *
-+=item Numerical Traps
-
--Barewords that used to look like strings to Perl will now look like subroutine
--calls if a subroutine by that name is defined before the compiler sees them.
--For example:
-+=item General data type traps
-
-- sub SeeYa { die "Hasta la vista, baby!" }
-- $SIG{'QUIT'} = SeeYa;
-+=item Context Traps - scalar, list contexts
-
--In Perl 4, that set the signal handler; in Perl 5, it actually calls the
--function! You may use the B<-w> switch to find such places.
-+=item Precedence Traps
-
--=item *
-+=item General Regular Expression Traps using s///, etc.
-
--Symbols starting with C<_> are no longer forced into package C<main>, except
--for $_ itself (and @_, etc.).
-+=item Subroutine, Signal, Sorting Traps
-
--=item *
-+=item OS Traps
-+
-+=item Unclassified Traps
-+
-+=back
-+
-+If you find an example of a conversion trap that is not listed here,
-+please submit it to Bill Middleton F<wjm@best.com> for inclusion.
-+Also note that at least some of these can be caught with C<-w>.
-+
-+=head2 Discontinuance, Depracation, and BugFix traps
-+
-+Anything that has been discontinued, depracated, or fixed as
-+a bug from perl4.
-+
-+=over 4
-+
-+=item * Discontinuance
-+
-+Symbols starting with "_" are no longer forced into package main, except
-+for C<$_> itself (and C<@_>, etc.).
-+
-+ package test;
-+ $_legacy = 1;
-+
-+ package main;
-+ print "\$_legacy is ",$_legacy,"\n";
-+
-+ # perl4 prints: $_legacy is 1
-+ # perl5 prints: $_legacy is
-+
-+=item * Depracation
-
- Double-colon is now a valid package separator in an identifier. Thus these
--behave differently in perl4 vs. perl5:
-+behave differently in perl4 vs. perl5, since the packages dont exist.
-
-- print "$a::$b::$c\n";
-+ $a=1;$b=2;$c=3;$var=4;
-+ print "$a::$b::$c ";
- print "$var::abc::xyz\n";
-+
-+ # perl4 prints: 1::2::3 4::abc::xyz
-+ # perl5 prints: 3
-
--=item *
-+Given that C<::> is now the preferred package delimiter, it is debatable
-+whether this should be classed as a bug or not.
-+(The older package delimiter, ' ,is used here)
-
--C<s'$lhs'$rhs'> now does no interpolation on either side. It used to
--interpolate C<$lhs> but not C<$rhs>.
-+ $x = 10 ;
-+ print "x=${'x}\n" ;
-+
-+ # perl4 prints: x=10
-+ # perl5 prints: Can't find string terminator "'" anywhere before EOF
-
--=item *
-+Also see precedence traps, for parsing C<$:>.
-
--The second and third arguments of splice() are now evaluated in scalar
--context (as the book says) rather than list context.
-+=item * BugFix
-
--=item *
-+The second and third arguments of C<splice()> are now evaluated in scalar
-+context (as the Camel says) rather than list context.
-+
-+ sub sub1{return(0,2) } # return a 2-elem array
-+ sub sub2{ return(1,2,3)} # return a 3-elem array
-+ @a1 = ("a","b","c","d","e");
-+ @a2 = splice(@a1,&sub1,&sub2);
-+ print join(' ',@a2),"\n";
-+
-+ # perl4 prints: a b
-+ # perl5 prints: c d e
-
--These are now semantic errors because of precedence:
-+=item * Discontinuance
-
-- shift @list + 20;
-- $n = keys %map + 20;
-+You can't do a C<goto> into a block that is optimized away. Darn.
-
--Because if that were to work, then this couldn't:
-+ goto marker1;
-
-- sleep $dormancy + 20;
-+ for(1){
-+ marker1:
-+ print "Here I is!\n";
-+ }
-+
-+ # perl4 prints: Here I is!
-+ # perl5 dumps core (SEGV)
-
--=item *
-+=item * Discontinuance
-+
-+It is no longer syntactically legal to use whitespace as the name
-+of a variable, or as a delimiter for any kind of quote construct.
-+Double darn.
-+
-+ $a = ("foo bar");
-+ $b = q baz ;
-+ print "a is $a, b is $b\n";
-+
-+ # perl4 prints: a is foo bar, b is baz
-+ # perl5 errors: Bare word found where operator expected
-+
-+=item * Discontinuance
-+
-+The archaic while/if BLOCK BLOCK syntax is no longer supported.
-+
-+ if { 1 } {
-+ print "True!";
-+ }
-+ else {
-+ print "False!";
-+ }
-+
-+ # perl4 prints: True!
-+ # perl5 errors: syntax error at test.pl line 1, near "if {"
-+
-+=item * BugFix
-+
-+The C<**> operator now binds more tightly than unary minus.
-+It was documented to work this way before, but didn't.
-+
-+ print -4**2,"\n";
-+
-+ # perl4 prints: 16
-+ # perl5 prints: -16
-+
-+=item * Discontinuance
-+
-+The meaning of C<foreach{}> has changed slightly when it is iterating over a
-+list which is not an array. This used to assign the list to a
-+temporary array, but no longer does so (for efficiency). This means
-+that you'll now be iterating over the actual values, not over copies of
-+the values. Modifications to the loop variable can change the original
-+values.
-+
-+ @list = ('ab','abc','bcd','def');
-+ foreach $var (grep(/ab/,@list)){
-+ $var = 1;
-+ }
-+ print (join(':',@list));
-+
-+ # perl4 prints: ab:abc:bcd:def
-+ # perl5 prints: 1:1:bcd:def
-+
-+To retain Perl4 semantics you need to assign your list
-+explicitly to a temporary array and then iterate over that. For
-+example, you might need to change
-+
-+ foreach $var (grep(/ab/,@list)){
-+
-+to
-+
-+ foreach $var (@tmp = grep(/ab/,@list)){
-+
-+Otherwise changing $var will clobber the values of @list. (This most often
-+happens when you use C<$_> for the loop variable, and call subroutines in
-+the loop that don't properly localize C<$_>.)
-+
-+=item * Depracation
-+
-+Some error messages will be different.
-+
-+=item * Discontinuance
-+
-+Some bugs may have been inadvertently removed. :-)
-+
-+=back
-+
-+=head2 Parsing Traps
-+
-+Perl4-to-Perl5 traps from having to do with parsing.
-+
-+=over 4
-+
-+=item * Parsing
-+
-+Note the space between . and =
-+
-+ $string . = "more string";
-+ print $string;
-+
-+ # perl4 prints: more string
-+ # perl5 prints: syntax error at - line 1, near ". ="
-+
-+=item * Parsing
-+
-+Better parsing in perl 5
-+
-+ sub foo {}
-+ &foo
-+ print("hello, world\n");
-+
-+ # perl4 prints: hello, world
-+ # perl5 prints: syntax error
-+
-+=item * Parsing
-+
-+"if it looks like a function, it is a function" rule.
-+
-+ print
-+ ($foo == 1) ? "is one\n" : "is zero\n";
-+
-+ # perl4 prints: is zero
-+ # perl5 warns: "Useless use of a constant in void context" if using -w
-+
-+=back
-+
-+=head2 Numerical Traps
-+
-+Perl4-to-Perl5 traps having to do with numerical operators,
-+operands, or output from same.
-+
-+=over 5
-+
-+=item * Numerical
-+
-+Formatted output and significant digits
-+
-+ print 7.373504 - 0, "\n";
-+ printf "%20.18f\n", 7.373504 - 0;
-+
-+ # Perl4 prints:
-+ 7.375039999999996141
-+ 7.37503999999999614
-+
-+ # Perl5 prints:
-+ 7.373504
-+ 7.37503999999999614
-+
-+=item * Numerical
-+
-+Large integer trap with autoincrement
-+
-+ $a = $b = 2147483647;
-+ print "$a $b\n";
-+ $a += 1;
-+ $b++;
-+ print "$a $b\n";
-+
-+ # perl4 prints:
-+ 2147483647 2147483647
-+ 2147483648 2147483648
-+
-+ # perl5 prints:
-+ 2147483647 2147483647
-+ 2147483648 -2147483648
-+
-+=item * Numerical
-+
-+Assignment of return values from numeric equality tests
-+does not work in perl5 when the test evaluates to false (0).
-+Logical tests now return an null, instead of 0
-+
-+ $p = ($test == 1);
-+ print $p,"\n";
-+
-+ # perl4 prints: 0
-+ # perl5 prints:
-+
-+Also see the L<General Regular Expression Traps> tests for another example
-+of this new feature...
-+
-+=back
-+
-+=head2 General data type traps
-+
-+Perl4-to-Perl5 traps involving most data-types, and their usage
-+within certain expressions and/or context.
-+
-+=over 5
-+
-+=item * (Arrays)
-+
-+Negative array subscripts now count from the end of the array.
-+
-+ @a = (1, 2, 3, 4, 5);
-+ print "The third element of the array is $a[3] also expressed as $a[-2] \n";
-+
-+ # perl4 prints: The third element of the array is 4 also expressed as
-+ # perl5 prints: The third element of the array is 4 also expressed as 4
-+
-+=item * (Arrays)
-+
-+Setting C<$#array> lower now discards array elements, and makes them
-+impossible to recover.
-+
-+ @a = (a,b,c,d,e);
-+ print "Before: ",join('',@a);
-+ $#a =1;
-+ print ", After: ",join('',@a);
-+ $#a =3;
-+ print ", Recovered: ",join('',@a),"\n";
-+
-+ # perl4 prints: Before: abcde, After: ab, Recovered: abcd
-+ # perl5 prints: Before: abcde, After: ab, Recovered: ab
-+
-+=item * (Hashes)
-+
-+Hashes get defined before use
-+
-+ local($s,@a,%h);
-+ die "scalar \$s defined" if defined($s);
-+ die "array \@a defined" if defined(@a);
-+ die "hash \%h defined" if defined(%h);
-+
-+ # perl4 prints:
-+ # perl5 dies: hash %h defined
-+
-+=item * (Globs)
-+
-+glob assignment from variable to variable will fail if the assigned
-+variable is localized subsequent to the assignment
-+
-+ @a = ("This is Perl 4");
-+ *b = *a;
-+ local(@a);
-+ print @b,"\n";
-+
-+ # perl4 prints: This is Perl 4
-+ # perl5 prints:
-+
-+ # Another example
-+
-+ *fred = *barney; # fred is aliased to barney
-+ @barney = (1, 2, 4);
-+ # @fred;
-+ print "@fred"; # should print "1, 2, 4"
-+
-+ # perl4 prints: 1 2 4
-+ # perl5 prints: Literal @fred now requires backslash
-+
-+=item * (Scalar String)
-+
-+Changes in unary negation (of strings)
-+This change effects both the return value and what it
-+does to auto(magic)increment.
-+
-+ $x = "aaa";
-+ print ++$x," : ";
-+ print -$x," : ";
-+ print ++$x,"\n";
-+
-+ # perl4 prints: aab : -0 : 1
-+ # perl5 prints: aab : -aab : aac
-+
-+=item * (Constants)
-+
-+perl 4 lets you modify constants:
-+
-+ $foo = "x";
-+ &mod($foo);
-+ for ($x = 0; $x < 3; $x++) {
-+ &mod("a");
-+ }
-+ sub mod {
-+ print "before: $_[0]";
-+ $_[0] = "m";
-+ print " after: $_[0]\n";
-+ }
-+
-+ # perl4:
-+ # before: x after: m
-+ # before: a after: m
-+ # before: m after: m
-+ # before: m after: m
-+
-+ # Perl5:
-+ # before: x after: m
-+ # Modification of a read-only value attempted at foo.pl line 12.
-+ # before: a
-+
-+=item * (Scalars)
-+
-+The behavior is slightly different for:
-+
-+ print "$x", defined $x
-+
-+ # perl 4: 1
-+ # perl 5: <no output, $x is not called into existence>
-+
-+=item * (Variable Suicide)
-+
-+Variable suicide behavior is more consistent under Perl 5.
-+Perl5 exhibits the same behavior for associative arrays and scalars,
-+that perl4 exhibits only for scalars.
-+
-+ $aGlobal{ "aKey" } = "global value";
-+ print "MAIN:", $aGlobal{"aKey"}, "\n";
-+ $GlobalLevel = 0;
-+ &test( *aGlobal );
-+
-+ sub test {
-+ local( *theArgument ) = @_;
-+ local( %aNewLocal ); # perl 4 != 5.001l,m
-+ $aNewLocal{"aKey"} = "this should never appear";
-+ print "SUB: ", $theArgument{"aKey"}, "\n";
-+ $aNewLocal{"aKey"} = "level $GlobalLevel"; # what should print
-+ $GlobalLevel++;
-+ if( $GlobalLevel<4 ) {
-+ &test( *aNewLocal );
-+ }
-+ }
-+
-+ # Perl4:
-+ # MAIN:global value
-+ # SUB: global value
-+ # SUB: level 0
-+ # SUB: level 1
-+ # SUB: level 2
-+
-+ # Perl5:
-+ # MAIN:global value
-+ # SUB: global value
-+ # SUB: this should never appear
-+ # SUB: this should never appear
-+ # SUB: this should never appear
-+
-+=back
-+
-+=head2 Context Traps - scalar, list contexts
-+
-+=over 5
-+
-+=item * (list context)
-+
-+The elements of argument lists for formats are now evaluated in list
-+context. This means you can interpolate list values now.
-+
-+ @fmt = ("foo","bar","baz");
-+ format STDOUT=
-+ @<<<<< @||||| @>>>>>
-+ @fmt;
-+ .
-+ write;
-+
-+ # perl4 errors: Please use commas to separate fields in file
-+ # perl5 prints: foo bar baz
-+
-+=item * (scalar context)
-+
-+The C<caller()> function now returns a false value in a scalar context
-+if there is no caller. This lets library files determine if they're
-+being required.
-+
-+ caller() ? (print "You rang?\n") : (print "Got a 0\n");
-+
-+ # perl4 errors: There is no caller
-+ # perl5 prints: Got a 0
-+
-+=item * (scalar context)
-+
-+The comma operator in a scalar context is now guaranteed to give a
-+scalar context to its arguments.
-+
-+ @y= ('a','b','c');
-+ $x = (1, 2, @y);
-+ print "x = $x\n";
-+
-+ # Perl4 prints: x = c # Thinks list context interpolates list
-+ # Perl5 prints: x = 3 # Knows scalar uses length of list
-+
-+=item * (list, builtin)
-+
-+C<sprintf()> funkiness (array argument converted to scalar array count)
-+This test could be added to t/op/sprintf.t
-+
-+ @z = ('%s%s', 'foo', 'bar');
-+ $x = sprintf(@z);
-+ if ($x eq 'foobar') {print "ok 2\n";} else {print "not ok 2 '$x'\n";}
-+
-+ # perl4 prints: ok 2
-+ # perl5 prints: not ok 2
-+
-+C<printf()> works fine, though:
-+
-+ printf STDOUT (@z);
-+ print "\n";
-+
-+ # perl4 prints: foobar
-+ # perl5 prints: foobar
-+
-+Probably a bug.
-+
-+=back
-+
-+=head2 Precedence Traps
-+
-+Perl4-to-Perl5 traps involving precedence order.
-+
-+=item *
-+
-+These are now semantic errors because of precedence:
-+
-+ @list = (1,2,3,4,5);
-+ %map = ("a",1,"b",2,"c",3,"d",4);
-+ $n = shift @list + 2; # first item in list plus 2
-+ print "n is $n, ";
-+ $m = keys %map + 2; # number of items in hash plus 2
-+ print "m is $m\n";
-+
-+ # perl4 prints: n is 3, m is 6
-+ # perl5 errors and fails to compile
-+
-+=item * Precedence
-
- The precedence of assignment operators is now the same as the precedence
- of assignment. Perl 4 mistakenly gave them the precedence of the associated
- operator. So you now must parenthesize them in expressions like
--
-+
- /foo/ ? ($a += 2) : ($a -= 2);
--
-+
- Otherwise
-
-- /foo/ ? $a += 2 : $a -= 2;
-+ /foo/ ? $a += 2 : $a -= 2
-
- would be erroneously parsed as
-
-@@ -408,115 +873,418 @@
-
- On the other hand,
-
-- $a += /foo/ ? 1 : 2;
-+ $a += /foo/ ? 1 : 2;
-
- now works as a C programmer would expect.
-
--=item *
-+=item * Precedence
-
--C<open FOO || die> is now incorrect. You need parens around the filehandle.
--While temporarily supported, using such a construct will
--generate a non-fatal (but non-suppressible) warning.
-+ open FOO || die;
-
--=item *
-+is now incorrect. You need parens around the filehandle.
-+Otherwise, perl5 leaves the statement as it's default precedence:
-
--The elements of argument lists for formats are now evaluated in list
--context. This means you can interpolate list values now.
-+ open(FOO || die);
-+
-+ # perl4 opens or dies
-+ # perl5 errors: Precedence problem: open FOO should be open(FOO)
-
--=item *
-+=item * Precedence
-
--You can't do a C<goto> into a block that is optimized away. Darn.
-+perl4 gives the special variable, C<$:> precedence, where perl5
-+treats C<$::> as main C<package>
-
--=item *
-+ $a = "x"; print "$::a"
-+
-+ # perl 4 prints: -:a
-+ # perl 5 prints: x
-+
-+=item * Precedence
-
--It is no longer syntactically legal to use whitespace as the name
--of a variable, or as a delimiter for any kind of quote construct.
--Double darn.
-+concatatination precedence over filetest operator?
-
--=item *
-+ -e $foo .= "q"
-+
-+ # perl4 prints: no output
-+ # perl5 prints: Can't modify -e in concatenation
-
--The caller() function now returns a false value in a scalar context if there
--is no caller. This lets library files determine if they're being required.
-+=back
-
--=item *
-+=head2 General Regular Expression Traps using s///, etc.
-+
-+All types of RE traps.
-+
-+=over 5
-+
-+=item * Regular Expression
-+
-+C<s'$lhs'$rhs'> now does no interpolation on either side. It used to
-+interpolate C<$lhs> but not C<$rhs>. (And still does not match a literal
-+'$' in string)
-+
-+ $a=1;$b=2;
-+ $string = '1 2 $a $b';
-+ $string =~ s'$a'$b';
-+ print $string,"\n";
-+
-+ # perl4 prints: $b 2 $a $b
-+ # perl5 prints: 1 2 $a $b
-+
-+=item * Regular Expression
-
- C<m//g> now attaches its state to the searched string rather than the
--regular expression.
-+regular expression. (Once the scope of a block is left for the sub, the
-+state of the searched string is lost)
-
--=item *
-+ $_ = "ababab";
-+ while(m/ab/g){
-+ &doit("blah");
-+ }
-+ sub doit{local($_) = shift; print "Got $_ "}
-+
-+ # perl4 prints: blah blah blah
-+ # perl5 prints: infinite loop blah...
-
--C<reverse> is no longer allowed as the name of a sort subroutine.
-+=item * Regular Expression
-
--=item *
-+If no parentheses are used in a match, Perl4 sets C<$+> to
-+the whole match, just like C<$&>. Perl5 does not.
-
--B<taintperl> is no longer a separate executable. There is now a B<-T>
--switch to turn on tainting when it isn't turned on automatically.
-+ "abcdef" =~ /b.*e/;
-+ print "\$+ = $+\n";
-+
-+ # perl4 prints: bcde
-+ # perl5 prints:
-
--=item *
-+=item * Regular Expression
-
--Double-quoted strings may no longer end with an unescaped C<$> or C<@>.
-+substitution now returns the null string if it fails
-
--=item *
-+ $string = "test";
-+ $value = ($string =~ s/foo//);
-+ print $value, "\n";
-+
-+ # perl4 prints: 0
-+ # perl5 prints:
-
--The archaic C<while/if> BLOCK BLOCK syntax is no longer supported.
-+Also see L<Numerical Traps> for another example of this new feature.
-
-+=item * Regular Expression
-
--=item *
-+C<s`lhs`rhs`> (using backticks) is now a normal substitution, with no
-+backtick expansion
-
--Negative array subscripts now count from the end of the array.
-+ $string = "";
-+ $string =~ s`^`hostname`;
-+ print $string, "\n";
-+
-+ # perl4 prints: <the local hostname>
-+ # perl5 prints: hostname
-
--=item *
-+=item * Regular Expression
-
--The comma operator in a scalar context is now guaranteed to give a
--scalar context to its arguments.
-+Stricter parsing of variables used in regular expressions
-
--=item *
-+ s/^([^$grpc]*$grpc[$opt$plus$rep]?)//o;
-+
-+ # perl4: compiles w/o error
-+ # perl5: with Scalar found where operator expected ..., near "$opt$plus"
-
--The C<**> operator now binds more tightly than unary minus.
--It was documented to work this way before, but didn't.
-+an added component of this example, apparantly from the same script, is
-+the actual value of the s'd string after the substitution.
-+C<[$opt]> is a character class in perl4 and an array subscript in perl5
-
--=item *
-+ $grpc = 'a';
-+ $opt = 'r';
-+ $_ = 'bar';
-+ s/^([^$grpc]*$grpc[$opt]?)/foo/;
-+ print ;
-+
-+ # perl4 prints: foo
-+ # perl5 prints: foobar
-
--Setting C<$#array> lower now discards array elements.
-+=item * Regular Expression
-
--=item *
-+Under perl5, C<m?x?> matches only once, like C<?x?>. Under perl4, it matched
-+repeatedly, like C</x/> or C<m!x!>.
-
--delete() is not guaranteed to return the old value for tie()d arrays,
--since this capability may be onerous for some modules to implement.
-+ $test = "once";
-+ sub match { $test =~ m?once?; }
-+ &match();
-+ if( &match() ) {
-+ # m?x? matches more then once
-+ print "perl4\n";
-+ } else {
-+ # m?x? matches only once
-+ print "perl5\n";
-+ }
-+
-+ # perl4 prints: perl4
-+ # perl5 prints: perl5
-
--=item *
-+
-+=back
-+
-+=head2 Subroutine, Signal, Sorting Traps
-+
-+The general group of Perl4-to-Perl5 traps having to do with
-+Signals, Sorting, and their related subroutines, as well as
-+general subroutine traps. Includes some OS-Specific traps.
-+
-+=over 5
-+
-+=item * (Signals)
-+
-+Barewords that used to look like strings to Perl will now look like subroutine
-+calls if a subroutine by that name is defined before the compiler sees them.
-+
-+ sub SeeYa { warn"Hasta la vista, baby!" }
-+ $SIG{'TERM'} = SeeYa;
-+ print "SIGTERM is now $SIG{'TERM'}\n";
-+
-+ # perl4 prints: SIGTERM is main'SeeYa
-+ # perl5 prints: SIGTERM is now main::1
-+
-+Use -w to catch this one
-+
-+=item * (Sort Subroutine)
-+
-+reverse is no longer allowed as the name of a sort subroutine.
-+
-+ sub reverse{ print "yup "; $a <=> $b }
-+ print sort reverse a,b,c;
-+
-+ # perl4 prints: yup yup yup yup abc
-+ # perl5 prints: abc
-+
-+=back
-+
-+=head2 OS Traps
-+
-+=over 5
-+
-+=item * (SysV)
-+
-+Under HPUX, and some other SysV OS's, one had to reset any signal handler,
-+within the signal handler function, each time a signal was handled with
-+perl4. With perl5, the reset is now done correctly. Any code relying
-+on the handler _not_ being reset will have to be reworked.
-+
-+5.002 and beyond uses sigaction() under SysV
-+
-+ sub gotit {
-+ print "Got @_... ";
-+ }
-+ $SIG{'INT'} = 'gotit';
-+
-+ $| = 1;
-+ $pid = fork;
-+ if ($pid) {
-+ kill('INT', $pid);
-+ sleep(1);
-+ kill('INT', $pid);
-+ } else {
-+ while (1) {sleep(10);}
-+ }
-+
-+ # perl4 (HPUX) prints: Got INT...
-+ # perl5 (HPUX) prints: Got INT... Got INT...
-+
-+=item * (SysV)
-+
-+Under SysV OS's, C<seek()> on a file opened to append C<E<gt>E<gt>> now does
-+the right thing w.r.t. the fopen() man page. e.g. - When a file is opened
-+for append, it is impossible to overwrite information already in
-+the file.
-+
-+ open(TEST,">>seek.test");
-+ $start = tell TEST ;
-+ foreach(1 .. 9){
-+ print TEST "$_ ";
-+ }
-+ $end = tell TEST ;
-+ seek(TEST,$start,0);
-+ print TEST "18 characters here";
-+
-+ # perl4 (solaris) seek.test has: 18 characters here
-+ # perl5 (solaris) seek.test has: 1 2 3 4 5 6 7 8 9 18 characters here
-+
-+
-+
-+=back
-+
-+=head2 Interpolation Traps
-+
-+=over 5
-+
-+=item * Interpolation
-+
-+@ now always interpolates an array in double-quotish strings.
-+
-+ print "To: someone@somewhere.com\n";
-+
-+ # perl4 prints: To:someone@somewhere.com
-+ # perl5 errors : Literal @somewhere now requires backslash
-+
-+=item * Interpolation
-+
-+Perl4-to-Perl5 traps having to do with how things get interpolated
-+within certain expressions, statements, contexts, or whatever.
-+
-+Double-quoted strings may no longer end with an unescaped $ or @.
-+
-+ $foo = "foo$";
-+ $bar = "bar@";
-+ print "foo is $foo, bar is $bar\n";
-+
-+ # perl4 prints: foo is foo$, bar is bar@
-+ # perl5 errors: Final $ should be \$ or $name
-+
-+Note: perl5 DOES NOT error on the terminating @ in $bar
-+
-+=item * Interpolation
-
- The construct "this is $$x" used to interpolate the pid at that
--point, but now tries to dereference $x. C<$$> by itself still
-+point, but now apparantly tries to dereference C<$x>. C<$$> by itself still
- works fine, however.
-
--=item *
-+ print "this is $$x\n";
-
--The meaning of foreach has changed slightly when it is iterating over a
--list which is not an array. This used to assign the list to a
--temporary array, but no longer does so (for efficiency). This means
--that you'll now be iterating over the actual values, not over copies of
--the values. Modifications to the loop variable can change the original
--values. To retain Perl 4 semantics you need to assign your list
--explicitly to a temporary array and then iterate over that. For
--example, you might need to change
-+ # perl4 prints: this is XXXx (XXX is the current pid)
-+ # perl5 prints: this is
-
-- foreach $var (grep /x/, @list) { ... }
-+=item * Interpolation
-+
-+Creation of hashes on the fly with C<eval "EXPR"> now requires either both
-+C<$>'s to be protected in the specification of the hash name, or both curlies
-+to be protected. If both curlies are protected, the result will be compatible
-+with perl4 and perl5. This is a very common practice, and should be changed
-+to use the block form of C<eval{}> if possible.
-+
-+ $hashname = "foobar";
-+ $key = "baz";
-+ $value = 1234;
-+ eval "\$$hashname{'$key'} = q|$value|";
-+ (defined($foobar{'baz'})) ? (print "Yup") : (print "Nope");
-+
-+ # perl4 prints: Yup
-+ # perl5 prints: Nope
-+
-+Changing
-+
-+ eval "\$$hashname{'$key'} = q|$value|";
-
- to
-
-- foreach $var (my @tmp = grep /x/, @list) { ... }
-+ eval "\$\$hashname{'$key'} = q|$value|";
-
--Otherwise changing C<$var> will clobber the values of @list. (This most often
--happens when you use C<$_> for the loop variable, and call subroutines in
--the loop that don't properly localize C<$_>.)
-+causes the following result:
-
--=item *
-+ # perl4 prints: Nope
-+ # perl5 prints: Yup
-
--Some error messages will be different.
-+or, changing to
-
--=item *
-+ eval "\$$hashname\{'$key'\} = q|$value|";
-
--Some bugs may have been inadvertently removed.
-+causes the following result:
-+
-+ # perl4 prints: Yup
-+ # perl5 prints: Yup
-+ # and is compatible for both versions
-+
-+
-+=item * Interpolation
-+
-+perl4 programs which unconsciously rely on the bugs in earlier perl versions.
-+
-+ perl -e '$bar=q/not/; print "This is $foo{$bar} perl5"'
-+
-+ # perl4 prints: This is not perl5
-+ # perl5 prints: This is perl5
-+
-+=item * Interpolation
-+
-+You also have to be careful about array references.
-+
-+ print "$foo{"
-+
-+ perl 4 prints: {
-+ perl 5 prints: syntax error
-+
-+=item * Interpolation
-+
-+Similarly, watch out for:
-+
-+ $foo = "array";
-+ print "\$$foo{bar}\n";
-+
-+ # perl4 prints: $array{bar}
-+ # perl5 prints: $
-+
-+Perl 5 is looking for C<$array{bar}> which doesn't exist, but perl 4 is
-+happy just to expand $foo to "array" by itself. Watch out for this
-+especially in C<eval>'s.
-+
-+=item * Interpolation
-+
-+C<qq()> string passed to C<eval>
-+
-+ eval qq(
-+ foreach \$y (keys %\$x\) {
-+ \$count++;
-+ }
-+ );
-+
-+ # perl4 runs this ok
-+ # perl5 prints: Can't find string terminator ")"
-+
-+=back
-+
-+=head2 Unclassified Traps
-+
-+Everything else.
-+
-+=over 5
-+
-+=item * Unclassified
-+
-+Existing dbm databases created under perl4 (or any other dbm/ndbm tool)
-+may cause the same script, run under perl5, to fail. The build of perl5
-+must have been linked with the same dbm/ndbm as the default for C<dbmopen()>
-+to function properly without C<tie>'ing to an extension dbm implementation.
-+
-+ dbmopen (%dbm, "file", undef);
-+ print "ok\n";
-+
-+ # perl4 prints: ok
-+ # perl5 prints: ok (IFF linked with -ldbm or -lndbm)
-+
-+=item * Unclassified
-+
-+C<require>/C<do> trap using returned value
-+
-+If the file doit.pl has:
-+
-+ sub foo {
-+ $rc = do "./do.pl";
-+ return 8;
-+ }
-+ print &foo, "\n";
-+
-+And the do.pl file has the following single line:
-+
-+ return 3;
-+
-+Running doit.pl gives the following:
-+
-+ # perl 4 prints: 3 (aborts the subroutine early)
-+ # perl 5 prints: 8
-+
-+Same behavior if you replace C<do> with C<require>.
-
- =back
-+
-+As always, if any of these are ever officially declared as bugs,
-+they'll be fixed and removed.
-+
generated by cgit (git 2.34.1) at 2024-11-28 06:44:28 +0800