Struct paho_mqtt::name_value::NameValueCollection

pub struct NameValueCollection { /* private fields */ }

A collection of C-compatible (NUL-terminated) string pairs that is useful with C APIs that require an array of string pair pointers, normally specified as const* MQTTAsync_nameValue

Implementations

impl NameValueCollection

pub fn new<N, V>(coll: &[(N, V)]) -> Self where
    N: AsRef<str>,
    V: AsRef<str>, 

Creates a NameValueCollection from a vector of string pair references.

Arguments

coll A collection of string pair references.

pub fn is_empty(&self) -> bool

Returns true if the collection contains elements.

pub fn len(&self) -> usize

Gets the number of strings in the collection.

pub fn as_c_arr_ptr(&self) -> *const MQTTAsync_nameValue

Gets the collection as a pointer to const C string pair pointers.

This returns a pointer that can be sent to a C API that takes a pointer to an array of name/value char pointer pairs, like const MQTTAsync_nameValue*

This function is inherently unsafe. The pointer it returns is only valid while the collection remains unmodified. In general, it should be requested when needed and not stored for future use.

Trait Implementations

impl Clone for NameValueCollection

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NameValueCollection

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for NameValueCollection

fn default() -> Self

Returns the “default value” for a type.

impl From<HashMap<&'_ str, &'_ str, RandomState>> for NameValueCollection

fn from(hmap: HashMap<&str, &str>) -> Self

Converts to this type from the input type.