To define an anonymous subroutine at runtime:
- $subref = sub BLOCK;
+ $subref = sub BLOCK; # no proto
+ $subref = sub (PROTO) BLOCK; # with proto
To import subroutines:
To call subroutines:
NAME(LIST); # & is optional with parentheses.
- NAME LIST; # Parentheses optional if pre-declared/imported.
- &NAME; # Passes current @_ to subroutine.
+ NAME LIST; # Parentheses optional if predeclared/imported.
+ &NAME; # Makes current @_ visible to called subroutine.
=head1 DESCRIPTION
via the C<do>, C<require>, or C<use> keywords, or even generated on the
fly using C<eval> or anonymous subroutines (closures). You can even call
a function indirectly using a variable containing its name or a CODE reference
-to it, as in C<$var = \&function>.
+to it.
The Perl model for function call and return values is simple: all
functions are passed as parameters one single flat list of scalars, and
Any arguments passed to the routine come in as the array @_. Thus if you
called a function with two arguments, those would be stored in C<$_[0]>
-and C<$_[1]>. The array @_ is a local array, but its values are implicit
-references (predating L<perlref>) to the actual scalar parameters. The
-return value of the subroutine is the value of the last expression
-evaluated. Alternatively, a return statement may be used to specify the
-returned value and exit the subroutine. If you return one or more arrays
-and/or hashes, these will be flattened together into one large
-indistinguishable list.
+and C<$_[1]>. The array @_ is a local array, but its elements are
+aliases for the actual scalar parameters. In particular, if an element
+C<$_[0]> is updated, the corresponding argument is updated (or an error
+occurs if it is not updatable). If an argument is an array or hash
+element which did not exist when the function was called, that element is
+created only when (and if) it is modified or if a reference to it is
+taken. (Some earlier versions of Perl created the element whether or not
+it was assigned to.) Note that assigning to the whole array @_ removes
+the aliasing, and does not update any arguments.
+
+The return value of the subroutine is the value of the last expression
+evaluated. Alternatively, a return statement may be used to exit the
+subroutine, optionally specifying the returned value, which will be
+evaluated in the appropriate context (list, scalar, or void) depending
+on the context of the subroutine call. If you specify no return value,
+the subroutine will return an empty list in a list context, an undefined
+value in a scalar context, or nothing in a void context. If you return
+one or more arrays and/or hashes, these will be flattened together into
+one large indistinguishable list.
Perl does not have named formal parameters, but in practice all you do is
assign to a my() list of these. Any variables you use in the function
sub get_line {
$thisline = $lookahead; # GLOBAL VARIABLES!!
- LINE: while ($lookahead = <STDIN>) {
+ LINE: while (defined($lookahead = <STDIN>)) {
if ($lookahead =~ /^[ \t]/) {
$thisline .= $lookahead;
}
upcase_in($v1, $v2); # this changes $v1 and $v2
sub upcase_in {
- for (@_) { tr/a-z/A-Z/ }
- }
+ for (@_) { tr/a-z/A-Z/ }
+ }
You aren't allowed to modify constants in this way, of course. If an
argument were actually literal and you tried to change it, you'd take a
upcase_in("frederick");
-It would be much safer if the upcase_in() function
+It would be much safer if the upcase_in() function
were written to return a copy of its parameters instead
of changing them in place:
($v3, $v4) = upcase($v1, $v2); # this doesn't
sub upcase {
+ return unless defined wantarray; # void context, do nothing
my @parms = @_;
- for (@parms) { tr/a-z/A-Z/ }
- # wantarray checks if we were called in list context
+ for (@parms) { tr/a-z/A-Z/ }
return wantarray ? @parms : $parms[0];
- }
+ }
Notice how this (unprototyped) function doesn't care whether it was passed
real scalars or arrays. Perl will see everything as one big long flat @_
Because like its flat incoming parameter list, the return list is also
flat. So all you have managed to do here is stored everything in @a and
-made @b an empty list. See L</"Pass by Reference"> for alternatives.
+made @b an empty list. See L<Pass by Reference> for alternatives.
A subroutine may be called using the "&" prefix. The "&" is optional
in modern Perls, and so are the parentheses if the subroutine has been
-pre-declared. (Note, however, that the "&" is I<NOT> optional when
+predeclared. (Note, however, that the "&" is I<NOT> optional when
you're just naming the subroutine, such as when it's used as an
argument to defined() or undef(). Nor is it optional when you want to
do an indirect subroutine call with a subroutine name or reference
&foo(); # the same
&foo; # foo() get current args, like foo(@_) !!
- foo; # like foo() IFF sub foo pre-declared, else "foo"
+ foo; # like foo() IFF sub foo predeclared, else "foo"
Not only does the "&" form make the argument list optional, but it also
disables any prototype checking on the arguments you do provide. This
is partly for historical reasons, and partly for having a convenient way
to cheat if you know what you're doing. See the section on Prototypes below.
+Function whose names are in all upper case are reserved to the Perl core,
+just as are modules whose names are in all lower case. A function in
+all capitals is a loosely-held convention meaning it will be called
+indirectly by the run-time system itself. Functions that do special,
+pre-defined things BEGIN, END, AUTOLOAD, and DESTROY--plus all the
+functions mentioned in L<perltie>. The 5.005 release adds INIT
+to this list.
+
=head2 Private Variables via my()
Synopsis:
Only alphanumeric identifiers may be lexically scoped--magical
builtins like $/ must currently be localized with "local" instead.
-Unlike dynamic variables created by the "local" statement, lexical
+Unlike dynamic variables created by the "local" operator, lexical
variables declared with "my" are totally hidden from the outside world,
including any called subroutines (even if it's the same subroutine called
from itself or elsewhere--every call gets its own copy).
+This doesn't mean that a my() variable declared in a statically
+I<enclosing> lexical scope would be invisible. Only the dynamic scopes
+are cut off. For example, the bumpx() function below has access to the
+lexical $x variable because both the my and the sub occurred at the same
+scope, presumably the file scope.
+
+ my $x = 10;
+ sub bumpx { $x++ }
+
(An eval(), however, can see the lexical variables of the scope it is
being evaluated in so long as the names aren't hidden by declarations within
the eval() itself. See L<perlref>.)
my $arg = shift; # name doesn't matter
$arg **= 1/3;
return $arg;
- }
+ }
The "my" is simply a modifier on something you might assign to. So when
you do assign to the variables in its argument list, the "my" doesn't
change whether those variables is viewed as a scalar or an array. So
- my ($foo) = <STDIN>;
+ my ($foo) = <STDIN>; # WRONG?
my @FOO = <STDIN>;
both supply a list context to the right-hand side, while
supplies a scalar context. But the following declares only one variable:
- my $foo, $bar = 1;
+ my $foo, $bar = 1; # WRONG
That has the same effect as
my $x = $x;
-can be used to initialize the new $x with the value of the old $x, and
+can be used to initialize the new $x with the value of the old $x, and
the expression
my $x = 123 and $x == 123
braces that delimit their controlled blocks; control expressions are
part of the scope, too. Thus in the loop
- while (my $line = <>) {
+ while (defined(my $line = <>)) {
$line = lc $line;
} continue {
print $line;
A my() has both a compile-time and a run-time effect. At compile time,
the compiler takes notice of it; the principle usefulness of this is to
-quiet C<use strict 'vars'>. The actual initialization doesn't happen
-until run time, so gets executed every time through a loop.
+quiet C<use strict 'vars'>. The actual initialization is delayed until
+run time, so it gets executed appropriately; every time through a loop,
+for example.
Variables declared with "my" are not part of any package and are therefore
never fully qualified with the package name. In particular, you're not
That will print out 20 and 10.
-You may declare "my" variables at the outermost scope of a file to
-hide any such identifiers totally from the outside world. This is similar
+You may declare "my" variables at the outermost scope of a file to hide
+any such identifiers totally from the outside world. This is similar
to C's static variables at the file level. To do this with a subroutine
-requires the use of a closure (anonymous function). If a block (such as
-an eval(), function, or C<package>) wants to create a private subroutine
-that cannot be called from outside that block, it can declare a lexical
-variable containing an anonymous sub reference:
+requires the use of a closure (anonymous function with lexical access).
+If a block (such as an eval(), function, or C<package>) wants to create
+a private subroutine that cannot be called from outside that block,
+it can declare a lexical variable containing an anonymous sub reference:
my $secret_version = '1.001-beta';
my $secret_sub = sub { print $secret_version };
This does not work with object methods, however; all object methods have
to be in the symbol table of some package to be found.
-Just because the lexical variable is lexically (also called statically)
-scoped doesn't mean that within a function it works like a C static. It
-normally works more like a C auto. But here's a mechanism for giving a
-function private variables with both lexical scoping and a static
-lifetime. If you do want to create something like C's static variables,
-just enclose the whole function in an extra block, and put the
-static variable outside the function but in the block.
+=head2 Peristent Private Variables
+
+Just because a lexical variable is lexically (also called statically)
+scoped to its enclosing block, eval, or do FILE, this doesn't mean that
+within a function it works like a C static. It normally works more
+like a C auto, but with implicit garbage collection.
+
+Unlike local variables in C or C++, Perl's lexical variables don't
+necessarily get recycled just because their scope has exited.
+If something more permanent is still aware of the lexical, it will
+stick around. So long as something else references a lexical, that
+lexical won't be freed--which is as it should be. You wouldn't want
+memory being free until you were done using it, or kept around once you
+were done. Automatic garbage collection takes care of this for you.
+
+This means that you can pass back or save away references to lexical
+variables, whereas to return a pointer to a C auto is a grave error.
+It also gives us a way to simulate C's function statics. Here's a
+mechanism for giving a function private variables with both lexical
+scoping and a static lifetime. If you do want to create something like
+C's static variables, just enclose the whole function in an extra block,
+and put the static variable outside the function but in the block.
{
- my $secret_val = 0;
+ my $secret_val = 0;
sub gimme_another {
return ++$secret_val;
- }
- }
+ }
+ }
# $secret_val now becomes unreachable by the outside
# world, but retains its value between calls to gimme_another
-If this function is being sourced in from a separate file
+If this function is being sourced in from a separate file
via C<require> or C<use>, then this is probably just fine. If it's
-all in the main program, you'll need to arrange for the my()
+all in the main program, you'll need to arrange for the my()
to be executed early, either by putting the whole block above
-your pain program, or more likely, placing merely a BEGIN
+your main program, or more likely, placing merely a BEGIN
sub around it to make sure it gets executed before your program
starts to run:
sub BEGIN {
- my $secret_val = 0;
+ my $secret_val = 0;
sub gimme_another {
return ++$secret_val;
- }
- }
+ }
+ }
See L<perlrun> about the BEGIN function.
+If declared at the outermost scope, the file scope, then lexicals work
+someone like C's file statics. They are available to all functions in
+that same file declared below them, but are inaccessible from outside of
+the file. This is sometimes used in modules to create private variables
+for the whole module.
+
=head2 Temporary Values via local()
B<NOTE>: In general, you should be using "my" instead of "local", because
local *merlyn = *randal; # now $merlyn is really $randal, plus
# @merlyn is really @randal, etc
local *merlyn = 'randal'; # SAME THING: promote 'randal' to *randal
- local *merlyn = \$randal; # just alias $merlyn, not @merlyn etc
+ local *merlyn = \$randal; # just alias $merlyn, not @merlyn etc
-A local() modifies its listed variables to be local to the enclosing
-block, (or subroutine, C<eval{}>, or C<do>) and I<any called from
-within that block>. A local() just gives temporary values to global
-(meaning package) variables. This is known as dynamic scoping. Lexical
-scoping is done with "my", which works more like C's auto declarations.
+A local() modifies its listed variables to be "local" to the enclosing
+block, eval, or C<do FILE>--and to I<any called from within that block>.
+A local() just gives temporary values to global (meaning package)
+variables. It does not create a local variable. This is known as
+dynamic scoping. Lexical scoping is done with "my", which works more
+like C's auto declarations.
If more than one variable is given to local(), they must be placed in
parentheses. All listed elements must be legal lvalues. This operator works
for $i ( 0 .. 9 ) {
$digits{$i} = $i;
- }
+ }
# assume this function uses global %digits hash
- parse_num();
+ parse_num();
# now temporarily add to %digits hash
if ($base12) {
supplies a scalar context.
+A note about C<local()> and composite types is in order. Something
+like C<local(%foo)> works by temporarily placing a brand new hash in
+the symbol table. The old hash is left alone, but is hidden "behind"
+the new one.
+
+This means the old variable is completely invisible via the symbol
+table (i.e. the hash entry in the C<*foo> typeglob) for the duration
+of the dynamic scope within which the C<local()> was seen. This
+has the effect of allowing one to temporarily occlude any magic on
+composite types. For instance, this will briefly alter a tied
+hash to some other implementation:
+
+ tie %ahash, 'APackage';
+ [...]
+ {
+ local %ahash;
+ tie %ahash, 'BPackage';
+ [..called code will see %ahash tied to 'BPackage'..]
+ {
+ local %ahash;
+ [..%ahash is a normal (untied) hash here..]
+ }
+ }
+ [..%ahash back to its initial tied self again..]
+
+As another example, a custom implementation of C<%ENV> might look
+like this:
+
+ {
+ local %ENV;
+ tie %ENV, 'MyOwnEnv';
+ [..do your own fancy %ENV manipulation here..]
+ }
+ [..normal %ENV behavior here..]
+
+It's also worth taking a moment to explain what happens when you
+localize a member of a composite type (i.e. an array or hash element).
+In this case, the element is localized I<by name>. This means that
+when the scope of the C<local()> ends, the saved value will be
+restored to the hash element whose key was named in the C<local()>, or
+the array element whose index was named in the C<local()>. If that
+element was deleted while the C<local()> was in effect (e.g. by a
+C<delete()> from a hash or a C<shift()> of an array), it will spring
+back into existence, possibly extending an array and filling in the
+skipped elements with C<undef>. For instance, if you say
+
+ %hash = ( 'This' => 'is', 'a' => 'test' );
+ @ary = ( 0..5 );
+ {
+ local($ary[5]) = 6;
+ local($hash{'a'}) = 'drill';
+ while (my $e = pop(@ary)) {
+ print "$e . . .\n";
+ last unless $e > 3;
+ }
+ if (@ary) {
+ $hash{'only a'} = 'test';
+ delete $hash{'a'};
+ }
+ }
+ print join(' ', map { "$_ $hash{$_}" } sort keys %hash),".\n";
+ print "The array has ",scalar(@ary)," elements: ",
+ join(', ', map { defined $_ ? $_ : 'undef' } @ary),"\n";
+
+Perl will print
+
+ 6 . . .
+ 4 . . .
+ 3 . . .
+ This is a test only a test.
+ The array has 6 elements: 0, 1, 2, undef, undef, 5
+
=head2 Passing Symbol Table Entries (typeglobs)
[Note: The mechanism described in this section was originally the only
passing multiple arrays in a single LIST, because normally the LIST
mechanism will merge all the array values so that you can't extract out
the individual arrays. For more on typeglobs, see
-L<perldata/"Typeglobs and FileHandles">.
+L<perldata/"Typeglobs and Filehandles">.
+
+=head2 When to Still Use local()
+
+Despite the existence of my(), there are still three places where the
+local() operator still shines. In fact, in these three places, you
+I<must> use C<local> instead of C<my>.
+
+=over
+
+=item 1. You need to give a global variable a temporary value, especially $_.
+
+The global variables, like @ARGV or the punctuation variables, must be
+localized with local(). This block reads in I</etc/motd>, and splits
+it up into chunks separated by lines of equal signs, which are placed
+in @Fields.
+
+ {
+ local @ARGV = ("/etc/motd");
+ local $/ = undef;
+ local $_ = <>;
+ @Fields = split /^\s*=+\s*$/;
+ }
+
+It particular, its important to localize $_ in any routine that assigns
+to it. Look out for implicit assignments in C<while> conditionals.
+
+=item 2. You need to create a local file or directory handle or a local function.
+
+A function that needs a filehandle of its own must use local() uses
+local() on complete typeglob. This can be used to create new symbol
+table entries:
+
+ sub ioqueue {
+ local (*READER, *WRITER); # not my!
+ pipe (READER, WRITER); or die "pipe: $!";
+ return (*READER, *WRITER);
+ }
+ ($head, $tail) = ioqueue();
+
+See the Symbol module for a way to create anonymous symbol table
+entries.
+
+Because assignment of a reference to a typeglob creates an alias, this
+can be used to create what is effectively a local function, or at least,
+a local alias.
+
+ {
+ local *grow = \&shrink; # only until this block exists
+ grow(); # really calls shrink()
+ move(); # if move() grow()s, it shrink()s too
+ }
+ grow(); # get the real grow() again
+
+See L<perlref/"Function Templates"> for more about manipulating
+functions by name in this way.
+
+=item 3. You want to temporarily change just one element of an array or hash.
+
+You can localize just one element of an aggregate. Usually this
+is done on dynamics:
+
+ {
+ local $SIG{INT} = 'IGNORE';
+ funct(); # uninterruptible
+ }
+ # interruptibility automatically restored here
+
+But it also works on lexically declared aggregates. Prior to 5.005,
+this operation could on occasion misbehave.
+
+=back
=head2 Pass by Reference
my @retlist = ();
foreach $aref ( @_ ) {
push @retlist, pop @$aref;
- }
+ }
return @retlist;
- }
+ }
-Here's how you might write a function that returns a
+Here's how you might write a function that returns a
list of keys occurring in all the hashes passed to it:
- @common = inter( \%foo, \%bar, \%joe );
+ @common = inter( \%foo, \%bar, \%joe );
sub inter {
my ($k, $href, %seen); # locals
foreach $href (@_) {
while ( $k = each %$href ) {
$seen{$k}++;
- }
- }
+ }
+ }
return grep { $seen{$_} == @_ } keys %seen;
- }
+ }
So far, we're using just the normal list return mechanism.
-What happens if you want to pass or return a hash? Well,
-if you're using only one of them, or you don't mind them
+What happens if you want to pass or return a hash? Well,
+if you're using only one of them, or you don't mind them
concatenating, then the normal calling convention is ok, although
-a little expensive.
+a little expensive.
Where people get into trouble is here:
return ($cref, $dref);
} else {
return ($dref, $cref);
- }
- }
+ }
+ }
It turns out that you can actually do this also:
return (\@c, \@d);
} else {
return (\@d, \@c);
- }
- }
+ }
+ }
Here we're using the typeglobs to do symbol table aliasing. It's
a tad subtle, though, and also won't work if you're using my()
sub openit {
my $name = shift;
local *FH;
- return open (FH, $path) ? \*FH : undef;
- }
+ return open (FH, $path) ? *FH : undef;
+ }
Although that will actually produce a small memory leak. See the bottom
of L<perlfunc/open()> for a somewhat cleaner way using the IO::Handle
sub func ($) {
my $n = shift;
print "you gave me $n\n";
- }
+ }
and someone has been calling it with an array or expression
returning a list:
starts scribbling on your @_ parameter list.
This is all very powerful, of course, and should be used only in moderation
-to make the world a better place.
+to make the world a better place.
=head2 Constant Functions
Functions with a prototype of C<()> are potential candidates for
-inlining. If the result after optimization and constant folding is a
-constant then it will be used in place of calls to the function.
-
-All of the following functions would be inlined.
-
- sub PI () { 3.14159 }
+inlining. If the result after optimization and constant folding is
+either a constant or a lexically-scoped scalar which has no other
+references, then it will be used in place of function calls made
+without C<&> or C<do>. Calls made using C<&> or C<do> are never
+inlined. (See constant.pm for an easy way to declare most
+constants.)
+
+The following functions would all be inlined:
+
+ sub pi () { 3.14159 } # Not exact, but close.
+ sub PI () { 4 * atan2 1, 1 } # As good as it gets,
+ # and it's inlined, too!
sub ST_DEV () { 0 }
sub ST_INO () { 1 }
sub FLAG_FOO () { 1 << 8 }
sub FLAG_BAR () { 1 << 9 }
sub FLAG_MASK () { FLAG_FOO | FLAG_BAR }
-
- sub OPT_BAZ () { 1 }
+
+ sub OPT_BAZ () { not (0x1B58 & FLAG_MASK) }
sub BAZ_VAL () {
if (OPT_BAZ) {
return 23;
}
}
-If you redefine a subroutine which was eligible for inlining you'll get
+ sub N () { int(BAZ_VAL) / 3 }
+ BEGIN {
+ my $prod = 1;
+ for (1..N) { $prod *= $_ }
+ sub N_FACTORIAL () { $prod }
+ }
+
+If you redefine a subroutine that was eligible for inlining, you'll get
a mandatory warning. (You can use this warning to tell whether or not a
particular subroutine is considered constant.) The warning is
considered severe enough not to be optional because previously compiled
(which changes the calling semantics, so beware) or by thwarting the
inlining mechanism in some other way, such as
- my $dummy;
sub not_inlined () {
- $dummy || 23
+ 23 if $];
}
=head2 Overriding Builtin Functions
Overriding may be done only by importing the name from a
module--ordinary predeclaration isn't good enough. However, the
-C<subs> pragma (compiler directive) lets you, in effect, pre-declare subs
+C<subs> pragma (compiler directive) lets you, in effect, predeclare subs
via the import syntax, and these names may then override the builtin ones:
use subs 'chdir', 'chroot', 'chmod', 'chown';
chdir $somewhere;
sub chdir { ... }
+To unambiguously refer to the builtin form, one may precede the
+builtin name with the special package qualifier C<CORE::>. For example,
+saying C<CORE::open()> will always refer to the builtin C<open()>, even
+if the current package has imported some other subroutine called
+C<&open()> from elsewhere.
+
Library modules should not in general export builtin names like "open"
or "chdir" as part of their default @EXPORT list, because these may
sneak into someone else's namespace and change the semantics unexpectedly.
they would get the default imports without the overrides.
+The foregoing mechanism for overriding builtins is restricted, quite
+deliberately, to the package that requests the import. There is a second
+method that is sometimes applicable when you wish to override a builtin
+everywhere, without regard to namespace boundaries. This is achieved by
+importing a sub into the special namespace C<CORE::GLOBAL::>. Here is an
+example that quite brazenly replaces the C<glob> operator with something
+that understands regular expressions.
+
+ package REGlob;
+ require Exporter;
+ @ISA = 'Exporter';
+ @EXPORT_OK = 'glob';
+
+ sub import {
+ my $pkg = shift;
+ return unless @_;
+ my $sym = shift;
+ my $where = ($sym =~ s/^GLOBAL_// ? 'CORE::GLOBAL' : caller(0));
+ $pkg->export($where, $sym, @_);
+ }
+
+ sub glob {
+ my $pat = shift;
+ my @got;
+ local(*D);
+ if (opendir D, '.') { @got = grep /$pat/o, readdir D; closedir D; }
+ @got;
+ }
+ 1;
+
+And here's how it could be (ab)used:
+
+ #use REGlob 'GLOBAL_glob'; # override glob() in ALL namespaces
+ package Foo;
+ use REGlob 'glob'; # override glob() in Foo:: only
+ print for <^[a-z_]+\.pm\$>; # show all pragmatic modules
+
+Note that the initial comment shows a contrived, even dangerous example.
+By overriding C<glob> globally, you would be forcing the new (and
+subversive) behavior for the C<glob> operator for B<every> namespace,
+without the complete cognizance or cooperation of the modules that own
+those namespaces. Naturally, this should be done with extreme caution--if
+it must be done at all.
+
+The C<REGlob> example above does not implement all the support needed to
+cleanly override perl's C<glob> operator. The builtin C<glob> has
+different behaviors depending on whether it appears in a scalar or list
+context, but our C<REGlob> doesn't. Indeed, many perl builtins have such
+context sensitive behaviors, and these must be adequately supported by
+a properly written override. For a fully functional example of overriding
+C<glob>, study the implementation of C<File::DosGlob> in the standard
+library.
+
+
=head2 Autoloading
If you call a subroutine that is undefined, you would ordinarily get an
immediate fatal error complaining that the subroutine doesn't exist.
(Likewise for subroutines being used as methods, when the method
-doesn't exist in any of the base classes of the class package.) If,
+doesn't exist in any base class of the class package.) If,
however, there is an C<AUTOLOAD> subroutine defined in the package or
packages that were searched for the original subroutine, then that
C<AUTOLOAD> subroutine is called with the arguments that would have been
my $program = $AUTOLOAD;
$program =~ s/.*:://;
system($program, @_);
- }
+ }
date();
who('am', 'i');
ls('-l');
-In fact, if you pre-declare the functions you want to call that way, you don't
+In fact, if you predeclare the functions you want to call that way, you don't
even need the parentheses:
use subs qw(date who ls);
=head1 SEE ALSO
-See L<perlref> for more on references. See L<perlxs> if you'd
-like to learn about calling C subroutines from perl. See
-L<perlmod> to learn about bundling up your functions in
-separate files.
+See L<perlref> for more about references and closures. See L<perlxs> if
+you'd like to learn about calling C subroutines from perl. See L<perlmod>
+to learn about bundling up your functions in separate files.
https://perl5.git.perl.org / perl5.git / blobdiff