[#boost-urls-grammar-lut_chars-08friend-02]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::operator&plus;
:relfileprefix: ../../../../
:mrdocs:


Return the union of two character sets&period;

== Synopsis


Declared in `&lt;https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/lut_chars.hpp#L299[boost&sol;url&sol;grammar&sol;lut&lowbar;chars&period;hpp]&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
friend
constexpr
xref:boost/urls/grammar/lut_chars.adoc[lut&lowbar;chars]
operator&plus;(
    xref:boost/urls/grammar/lut_chars.adoc[lut&lowbar;chars] const& cs0,
    xref:boost/urls/grammar/lut_chars.adoc[lut&lowbar;chars] const& cs1) noexcept;
----

== Description


This function returns a new character        set which contains all of the characters        in `cs0` as well as all of the characters        in `cs`&period;


=== Example

This creates a character set which        includes all letters and numbers 

[,cpp]
----
constexpr lut_chars alpha_chars(
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "abcdefghijklmnopqrstuvwxyz");

constexpr lut_chars alnum_chars = alpha_chars + "0123456789";
----

=== Complexity

Constant&period;



== Return Value


The new character set&period;



== Parameters


|===
| Name | Description

| *cs0*
| A character to join


| *cs1*
| A character to join


|===



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