Re^4: Wrong idioms (open $fh, '<', undef)

[Anonymous Monk]

What are you talking about?

[vsespb]

I mean open does not detect error if you "open" a directory. Also last code with "wantarray" and "scalar" looks useless.

[Anonymous Monk]

I mean open does not detect error if you "open" a directory.

Sure it does

$ perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ "
Permission denied
Access is denied

$ perl -e " open $dirname, q/../ or die join qq/\n/, $!,$^E,grep( { $!
+{$_} } keys %! ) "
Permission denied
Access is denied
ERROR_INVALID_DATA
EMARCH_ENC_I17_IMM5C_INST_WORD_POS_X
EMR_SETBRUSHORGEX
EVENT_SYSTEM_CONTEXTHELPEND
EACCES at -e line 1.

Also last code with "wantarray" and "scalar" looks useless.

No, its is not useless. You must not know perl well.

[vsespb]

perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ "

You must be running Windows? or? Cygwin?

Under linux:

perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ "
bash: !,: event not found

perl -e ' open $dirname, q/../ or die $!, $/, $^E, $/ '
(no error)

for wantarray:

use strict;
use warnings;

sub array_func
{
  my ($arg) = @_;
  if (wantarray) {
   return map { $arg } 1..3;
  } else {
   return map { $arg*2 } 1..5;
  }
}

sub uni_func
{
    my ($arg) = @_;
    return wantarray ?
           array_func($arg) :
           scalar array_func($arg);
}

sub small_func
{
    my ($arg) = @_;
    return array_func($arg) ;
}

print join(';', uni_func(7));
print "\n";
print scalar(uni_func(7));
print "\n";


print join(';', small_func(7));
print "\n";
print scalar(small_func(7));
print "\n";

print join(';', array_func(7));
print "\n";
print scalar array_func(7);
print "\n";
__END__
prints:
7;7;7
5
7;7;7
5
7;7;7
5

what's the point in using 'wantarray' in uni_func here?