NAME

       B::Hooks::OP::Check::EntersubForCV - Invoke callbacks on construction of entersub OPs for
       certain CVs

SYNOPSIS

   From Perl
           sub foo {}

           use B::Hooks::OP::Check::EntersubForCV
               \&foo => sub { warn "entersub for foo() being compiled" };

           foo(); # callback is invoked when this like is compiled

           no B::Hooks::OP::Check::EntersubForCV \&foo;

           foo(); # callback isn't invoked

   From C/XS
           #include "hook_op_check_entersubforcv.h"

           STATIC OP *
           my_callback (pTHX_ OP *op, CV *cv, void *user_data) {
               /* ... */
               return op;
           }

           hook_op_check_id id;

           /* register callback */
           id = hook_op_check_entersubforcv (cv, my_callback, NULL);

           /* unregister */
           hook_op_check_entersubforcv_remove (id);

DESCRIPTION

Perl API

   import / register
           use B::Hooks::OP::Check::EntersubForCV
               \&code => \&handler;

           # or
           my $id = B::Hooks::OP::Check::EntersubForCV::register(\&code => \&handler);

       Register "handler" to be executed when an entersub opcode for the CV "code" points to is
       compiled.

       When using "register" an id that can be used for later removal of the handler using
       "unregister" is returned.

   unimport / unregister
           no B::Hooks::OP::Check::EntersubForCV \&code;

           # or
           B::Hooks::OP::Check::EntersubForCV::unregister($id);

       Stop calling the registered handler for "code" for all entersubs after this.

C API

   TYPES
       OP *(*hook_op_check_entersubforcv_cb) (pTHX_ OP *, CV *, void *)

       The type the handlers need to implement.

   FUNCTIONS
       hook_op_check_id hook_op_check_entersubforcv (CV *cv, hook_op_check_entersubforcv_cb cb,
       void *user_data)

       Register the callback "cb" to be called when an entersub opcode for "cv" is compiled.
       "user_data" will be passed to the callback as the last argument.

       Returns an id that can be used to remove the handler using
       "hook_op_check_entersubforcv_remove".

       void *hook_op_check_entersubforcv_remove (hook_op_check_id id)

       Remove a previously registered handler referred to by "id".

       Returns the user data that was associated with the handler.

SEE ALSO

       B::Hooks::OP::Check

AUTHOR

       Florian Ragwitz <rafl@debian.org>

COPYRIGHT AND LICENSE

       Copyright (c) 2008, 2009 Florian Ragwitz

       Copyright (c) 2011, 2012, 2017 Andrew Main (Zefram)

       This module is free software.

       You may distribute this code under the same terms as Perl itself.