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

# warn

## Synopsis

```perl
warn "something looks wrong";
warn "problem at $file line $line\n";
warn $object;
```

## Description

Issues a warning message to STDERR without terminating the program.

Prints the argument to STDERR.  If the string does not end with a
newline, Perl appends ` at FILE line LINE`.

If `$SIG{__WARN__}` is set to a code reference, that handler is
called with the warning message as its sole argument instead of
printing to STDERR.  The handler runs in void context and its
return value is discarded.

## See also

die, Carp