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Perl Programming/Keywords/UNITCHECK
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Perl undef unless Keywords
The UNITCHECK keyword
UNITCHECK is one of five code blocks that are executed at the beginning and end of a program by Perl. It is useful to catch the transition between the compilation phase and execution phase of the main program.
Although it can be prefixed with sub, this is not considered a good programming practice, as these blocks are not a subroutine.
Syntax
UNITCHECK BLOCK
See also
BEGIN
CHECK
END
INIT
Perl undef unless Keywords