in reply to restore overridden XS methods

It seems that saving and restoring the glob doesn't work, but saving and restoring the CODE entry in the glob works for me:

perl -MTime::HiRes -le "my $x=*Time::HiRes::gettimeofday{CODE};*Time::
+HiRes::gettimeofday = sub(){42};print Time::HiRes::gettimeofday; *Tim
+e::HiRes::gettimeofday = $x;print Time::HiRes::gettimeofday"

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or, reformatted and untested:

use strict;
use Time::HiRes;

my $x=*Time::HiRes::gettimeofday{CODE};
*Time::HiRes::gettimeofday = sub(){42};
print "Modified: ", Time::HiRes::gettimeofday,"\n";
*Time::HiRes::gettimeofday = $x;
print "Restored: ", Time::HiRes::gettimeofday

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Replies are listed 'Best First'.
Re^2: restore overridden XS methods
by bart (Canon) on Mar 01, 2007 at 12:04 UTC
    Under -w, I get: 
    Subroutine gettimeofday redefined at z:\test.pl line 6.
Constant subroutine gettimeofday redefined at z:\test.pl line 8.
Modified: 42
Restored: 1172750176936000
    So, it works, kinda. With warnings.

    But unfortunately, local does not work: 

    #! perl -w
use strict;
use Time::HiRes;
{
    local *Time::HiRes::gettimeofday{CODE} = sub(){42};
    print "Modified: ", Time::HiRes::gettimeofday,"\n";
}
print "Restored: ", Time::HiRes::gettimeofday

    [download]
    This results in the following compile time error: 
    Can't modify glob elem in local at z:\test.pl line 5, near "} ="
Execution of z:\test.pl aborted due to compilation errors.
[reply]
[d/l]

      local works if you use glob assignment syntax: 

      { 
    local *Time::HiRes::gettimeofday = sub { print 42; }; 
    print Time::HiRes::gettimeofday(); 
};;
Subroutine Time::HiRes::gettimeofday redefined at (eval 4) line 1, <ST
+DIN> line 2.
42
1
print Time::HiRes::gettimeofday();;
1172754765 437500

      [download]
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
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[d/l]
        Clever. The only problem I see is that if there are other variable types attached to the name Time::HiRes::gettimeofday, such as $Time::HiRes::gettimeofday or @Time::HiRes::gettimeofday, that those will be overridden too.

        I don't think it matters for this particular case — or even, in most cases.

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[d/l]
[select]
Re^2: restore overridden XS methods
by dk (Chaplain) on Mar 01, 2007 at 10:38 UTC
    Aha! It was {CODE} I was missing. Thank you very much and ++ . /me gone reading perlref.
[reply]
[d/l]

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