# `Exonerate.Formats.Hostname`
[🔗](https://github.com/E-xyza/exonerate/blob/master/lib/exonerate/formats/hostname.ex#L1)

Module which provides a macro that generates special code for a hostname
filter.

the format is governed by section 2.1 of RFC 1123, which
modifies RFC 952:
https://www.rfc-editor.org/rfc/rfc1123.txt
https://www.rfc-editor.org/rfc/rfc952.txt

# `filter`
*macro* 

Creates a parser `~hostname/1`.

This function returns `{:ok}` if the passed string is a valid hostname, or
`{:error, reason}` if it is not.

The function will only be created once per module, and it is safe to call
the macro more than once.

## Options:
- `:name` (atom): the name of the function to create.  Defaults to
  `:"~hostname"`

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*Consult [api-reference.md](api-reference.md) for complete listing*