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

# require

## Synopsis

```perl
require 5.036;              # version check
require Carp;               # load Carp.pm via @INC
require "config.pl";        # load a file by path
```

## Description

Loads and executes a Perl file or module, caching it in `%INC` so
that subsequent calls for the same module are no-ops.

Behaviour depends on the argument type:

1. **Version number** (numeric or v-string): asserts that the Perl
   version is at least that value.  pperl claims 5.42 compatibility,
   so any 5.x requirement succeeds; 6+ dies.

2. **Bareword / string**: converts `Foo::Bar` to `Foo/Bar.pm`, then
   searches `@INC` for the file.  If already present in `%INC`, the
   call is a no-op.  Otherwise the file is compiled and executed in
   a sub-interpreter, subs are registered, and `%INC` is updated.

Dies with `"Can't locate ..."` if the file is not found.  Returns 1
on success.

## See also

use, do, eval, `@INC`, `%INC`