[#boost-urls-grammar-operator_plus]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::operator+
:relfileprefix: ../../../
:mrdocs:


Return the union of two character sets.

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/lut_chars.hpp#L299[boost/url/grammar/lut_chars.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:boost/urls/grammar/lut_chars.adoc[lut_chars]
operator+(
    xref:boost/urls/grammar/lut_chars.adoc[lut_chars] const& cs0,
    xref:boost/urls/grammar/lut_chars.adoc[lut_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`.


=== 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.



== Return Value


The new character set.



== Parameters


|===
| Name | Description

| *cs0*
| A character to join


| *cs1*
| A character to join


|===



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