[#boost-urls-grammar-operator_minus]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/grammar.adoc[grammar]::operator&hyphen;
:relfileprefix: ../../../
:mrdocs:

Return a new character set by subtracting

== Synopsis

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

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:boost/urls/grammar/lut_chars.adoc[lut&lowbar;chars]
operator&hyphen;(
    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 is formed from all of the characters in `cs0` which are not in `cs`&period;

== Example

This statement declares a character set containing all the lowercase letters which are not vowels&colon;

[,cpp]
----
constexpr lut_chars consonants = lut_chars("abcdefghijklmnopqrstuvwxyz") - "aeiou";
----
== Complexity

Constant&period;

== Return Value

The new character set&period;

== Parameters

[cols="1,4"]
|===
|Name|Description

| *cs0*
| A character set to join&period;
| *cs1*
| A character set to join&period;
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#
