[#boost-urls-grammar-ci_hash]
= xref:boost/urls/grammar/ci_hash.adoc[boost::urls::grammar::ci_hash]
:relfileprefix: ../../../
:mrdocs:

A case‐insensitive hash function object for strings

== Synopsis

Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/ci_string.hpp#L287[boost/url/grammar/ci_string.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
using ci_hash = /* implementation-defined */;
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== Description

The hash function is non‐cryptographic and not hardened against algorithmic complexity attacks. This is a suitable hash function for unordered containers. The function is defined only for strings containing low‐ASCII characters.

== Example
[,cpp]
----
boost::unordered_map< std::string, std::string, ci_hash, ci_equal > m1;

std::unordered_map  < std::string, std::string, ci_hash, ci_equal > m2; // (since C++20)
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== See Also

xref:boost/urls/grammar/ci_equal.adoc[`ci&lowbar;equal`], xref:boost/urls/grammar/ci_less.adoc[`ci&lowbar;less`]&period;


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