Re^3: Copy a builtin sub to a different name and then override

> still the same problem with this:

Really?

You still have Deep recursion on anonymous subroutine ?

As I said that's the normal way to install a wrapper, but in the case of builtins it seems risky.

calling CORE::sleep() should be the recommended way.

... but I seem to remember reading that overriding sleep used to be problematic.(?)

I'll look tomorrow into it.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^4: Copy a builtin sub to a different name and then override by bliako (Abbot) on Jun 01, 2018 at 23:36 UTC
No that's fine, your later suggestion `CORE::sleep()` worked great! thanks	[reply] [d/l]
Re^5: Copy a builtin sub to a different name and then override by LanX (Saint) on Jun 02, 2018 at 00:19 UTC
and here is the reason why, at least with 5.16 `warn $]; warn \&CORE::GLOBAL::sleep; warn \&CORE::sleep; &CORE::GLOBAL::sleep(3);` [download] `5.016003 at d:/Users/lanx/pm/core_sleep.pl line 1. CODE(0x328420) at d:/Users/lanx/pm/core_sleep.pl line 4. CODE(0x349718) at d:/Users/lanx/pm/core_sleep.pl line 5. <-- differen +t! Undefined subroutine &CORE::GLOBAL::sleep called at d:/Users/lanx/pm/c +ore_sleep.pl line 7.` [download] You are trying to build a wrapper around an non-existent function. You haven't told us which version you use, but I doubt that `CORE::GLOBAL::` is populated by default. What you originally tried, something like: `old = CORE::GLOBAL::sleep` is aliasing the two symbols (two symbols pointing to the same typeglob) But after populating the code slot with `CORE::GLOBAL::sleep = sub{}` both will point to the same sub. `old = CORE::GLOBAL::sleep; CORE::GLOBAL::sleep = sub { warn " ** beware of morons "}; &old(); # oops warn \&CORE::GLOBAL::sleep; warn \&old;` [download] ` beware of morons at d:/Users/lanx/pm/core_sleep.pl line 2. CODE(0x4c9478) at d:/Users/lanx/pm/core_sleep.pl line 7. CODE(0x4c9478) at d:/Users/lanx/pm/core_sleep.pl line 8. <-- identical +!` [download] That's why you get a circular call! Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery} update same with 5.18 on linux** `lanx@ubuntu14-large:~$ perl warn $]; warn \&CORE::GLOBAL::sleep; warn \&CORE::sleep; &CORE::GLOBAL::sleep(3); __END__ 5.018002 at - line 1. CODE(0x1804cb8) at - line 2. CODE(0x1830398) at - line 3. Undefined subroutine &CORE::GLOBAL::sleep called at - line 4.` [download] `lanx@ubuntu14-large:~$ perl old = CORE::GLOBAL::sleep; CORE::GLOBAL::sleep = sub { warn " * beware of morons "}; &old(); # oops warn \&CORE::GLOBAL::sleep; warn \&old; __END__ beware of morons ** at - line 2. CODE(0x2089448) at - line 5. CODE(0x2089448) at - line 6.` [download]	[reply] [d/l] [select]
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