A query parameter

Synopsis

Declared in header <boost/url/param.hpp>

struct param_pct_view;

Member Functions

Name

Description

operator param

Conversion

operator param_view

operator→

param_pct_view [constructor]

Construction

Constructor

Data Members

Name

Description

has_value

True if a value is present

key

The key

value

The value

Description

Objects of this type represent a single key and value pair in a query string where a key is always present and may be empty, while the presence of a value is indicated by has_value equal to true. An empty value is distinct from no value.

The strings may have percent escapes, and offer an additional invariant: they never contain an invalid percent-encoding.

For most usages, key comparisons are case-sensitive and duplicate keys in a query are possible. However, it is the authority that has final control over how the query is interpreted.

Keys and values in this object reference external character buffers. Ownership of the buffers is not transferred; the caller is responsible for ensuring that the assigned buffers remain valid until they are no longer referenced.

BNF

query-params    = query-param *( "&" query-param )
query-param     = key [ "=" value ]
key             = *qpchar
value           = *( qpchar / "=" )

Specification

See Also

param , param_view .