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

# binmode

## Synopsis

```perl
binmode(STDOUT);              # set binary mode (no CRLF translation)
binmode(STDOUT, ":utf8");     # set UTF-8 encoding layer
binmode(STDOUT, ":raw");      # remove all layers
binmode($fh, ":encoding(UTF-8)");
```

## Description

Sets the I/O discipline (encoding layer) for a filehandle.

Configures the encoding layer on a filehandle.  When called with
just a filehandle, sets binary mode (disabling any CRLF
translation, though Linux does not perform CRLF translation by
default).  When called with a layer string, applies the specified
encoding.

Currently recognized layers:
- `:utf8`, `:encoding(UTF-8)` -- mark the handle as UTF-8
- `:raw`, `:bytes` -- mark the handle as raw bytes

Returns true on success, false on failure.

## See also

open, PerlIO, Encode