---
name: defined
status: documented
runtime: pp
source: src/runtime/pp/array_ops.rs
---
```{index} single: defined; Perl built-in (pp runtime)
```

# defined

## Synopsis

```perl
if (defined $x)        { ... }
if (defined &func)     { ... }   # is sub defined (not a stub)?
if (defined $hash{$k}) { ... }
```

## Description

Tests whether a value is defined (not `undef`).

Pops one value from the stack and pushes 1 if it is defined, 0
otherwise. For code values (`Cv`), "defined" means the CV has
actual executable code and is not merely an empty stub. For all
other types, delegates to `Sv::is_defined()`.

## See also

undef, exists