http://www.perlmonks.org?node_id=1001814


in reply to Data::Diver polluting $!

philkime:

The documentation, in the $! section, states:

$! If used numerically, yields the current value of the C "errno" variable, or in other words, if a system or library call fails, it sets this variable. This means that the value of $! is meaningful only immediately after a failure...

A bit earlier, just after the Error Variables heading, it mentions that:

The variables $@, $!, $^E, and $? contain information about different types of error conditions ... They correspond to errors detected by the Perl interpreter, C library, operating system, or an external program, respectively.

So the long and short of it is that using the value of $! at any time other than just after a failed operation involving the C library is a bug.

...roboticus

When your only tool is a hammer, all problems look like your thumb.