---
name: Internals
runtime: pp
source: src/native/Internals/pp.rs
---
```{index} single: Internals; Perl module (pp runtime)
```

# Internals

Native implementation of Internals

Provides internal Perl functions that manipulate SV flags.

Perl equivalent: Internals (core module, always available)

# Functions

## SvREADONLY
Query or set the readonly flag on an SV. With one argument, returns the
current readonly status. With two arguments, sets or clears the flag.

    my $ro = Internals::SvREADONLY($sv);      # query
    Internals::SvREADONLY($sv, 1);             # make readonly
    Internals::SvREADONLY($sv, 0);             # make writable

## SvREFCNT
Returns the reference count of an SV. Always returns 1 in PetaPerl
(Rust uses `Arc` refcounting, not Perl's SV refcount).

    my $cnt = Internals::SvREFCNT($sv);

## hv_clear_placeholders
No-op. In perl5 this removes placeholder entries from restricted hashes.
PetaPerl does not implement restricted hashes, so this is a silent no-op.

    Internals::hv_clear_placeholders(\%hash);