Internals - phpMan

NAME
    Internals - Reserved special namespace for internals related functions

SYNOPSIS
        $is_ro= Internals::SvREADONLY($x)
        $refcnt= Internals::SvREFCNT($x)
        hv_clear_placeholders(%hash);

DESCRIPTION
    The Internals namespace is used by the core Perl development team to
    expose certain low level internals routines for testing and other
    purposes.

    In theory these routines were not and are not intended to be used
    outside of the perl core, and are subject to change and removal at any
    time.

    In practice people have come to depend on these over the years, despite
    being historically undocumented, so we will provide some level of
    forward compatibility for some time. Nevertheless you can assume that
    any routine documented here is experimental or deprecated and you should
    find alternatives to their use.

  FUNCTIONS
    SvREFCNT(THING [, $value])
        Historically Perl has been a refcounted language. This means that
        each variable tracks how many things reference it, and when the
        variable is no longer referenced it will automatically free itself.
        In theory Perl code should not have to care about this, and in a
        future version Perl might change to some other strategy, although in
        practice this is unlikely.

        This function allows one to violate the abstraction of variables and
        get or set the refcount of a variable, and in generally is really
        only useful in code that is testing refcount behavior.

        *NOTE* You are strongly discouraged from using this function in
        non-test code and especially discouraged from using the set form of
        this function. The results of doing so may result in segmentation
        faults or other undefined behavior.

    SvREADONLY(THING, [, $value])
        Set or get whether a variable is readonly or not. Exactly what the
        readonly flag means depend on the type of the variable affected and
        the version of perl used.

        You are strongly discouraged from using this function directly. It
        is used by various core modules, like "Hash::Util", and the
        "constant" pragma to implement higher-level behavior which should be
        used instead.

        See the core implementation for the exact meaning of the readonly
        flag for each internal variable type.

    hv_clear_placeholders(%hash)
        Clear any placeholders from a locked hash. Should not be used
        directly. You should use the wrapper functions provided by
        Hash::Util instead. As of 5.25 also available as "
        Hash::Util::_clear_placeholders(%hash) "

AUTHOR
    Perl core development team.

SEE ALSO
    perlguts Hash::Util constant universal.c

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