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


Match a decimal octet

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/grammar/dec_octet_rule.hpp#L104[boost/url/grammar/dec_octet_rule.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr /* implementation-defined */::xref:boost/urls/grammar/implementation_defined/dec_octet_rule_t.adoc[dec_octet_rule_t] dec_octet_rule = {};
----

== Description


A decimal octet is precise way of    saying a number from 0 to 255. These    are commonly used in IPv4 addresses.


=== Value Type

[,cpp]
----
using value_type = unsigned char;
----

=== Example

Rules are used with the function xref:boost/urls/grammar/parse-02.adoc[parse].

[,cpp]
----
system::result< unsigned char > rv = parse( "255", dec_octet_rule );
----

=== BNF

[,cpp]
----
dec-octet   = DIGIT                 ; 0-9
            / %x31-39 DIGIT         ; 10-99
            / "1" 2DIGIT            ; 100-199
            / "2" %x30-34 DIGIT     ; 200-249
            / "25" %x30-35          ; 250-255
----

=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.2.2[3&period;2&period;2&period;  Host (rfc3986)]



== See Also


xref:boost/urls/grammar/parse-02.adoc[parse]&period;






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