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Programming Perl

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7.2.76 vars - Predeclare Global Variable Names

use vars qw($frob @mung %seen);

This module predeclares all variables whose names are in the list, allowing you to use them under use strict, and disabling any typo warnings.

Packages such as the AutoLoader and SelfLoader that delay loading of subroutines within packages can create problems with file-scoped lexicals defined using my. This is because they move the subroutines outside the scope of the lexical variables. While the use vars pragma cannot duplicate the effect of file-scoped lexicals (total transparency outside of the file), it can act as an acceptable substitute by pre-declaring global symbols, ensuring their availability to the routines whose loading was delayed.

See also the subs module.


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7.2.75 Time::Local - Efficiently Compute Time from Local and GMT TimeBook Index8. Other Oddments