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);

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.

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.