Struct paho_mqtt::string_collection::StringCollection

pub struct StringCollection { /* private fields */ }

A collection of C-compatible (NUL-terminated) strings that is useful with C API’s that require an array of strings, normally specified as: const char* arr[] or const char** arr

Implementations

impl StringCollection

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

Creates a StringCollection from a vector of string references.

Arguments

coll A collection of string 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 *const c_char

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

This returns a pointer that can be sent to a C API that takes a pointer to an array of char pointers, like const char* arr[] 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.

pub fn as_c_arr_mut_ptr(&self) -> *const *mut c_char

Gets the collection as a pointer to mutable C string pointers.

This returns a pointer that can be sent to a C API that takes a pointer to an array of mutable char pointers, like char* arr[] 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.

This function is required due to the lax nature of the use of const strings in the C API. Hopefully the API will be fixed and this function can be removed

Trait Implementations

impl Clone for StringCollection

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 StringCollection

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

Formats the value using the given formatter.

impl Default for StringCollection

fn default() -> Self

Returns the “default value” for a type.