From cppreference.com
size_typemax_bucket_count()const;(since C++11)Returns the maximum number of buckets the container is able to hold due to system or library implementation limitations.
Parameters
(none)
Return value
Maximum number of buckets.
Complexity
Constant.
Example
Run this code
#include<iostream>#include<unordered_set>intmain(){structHa{std::size_toperator()(longx)const{returnstd::hash<long>{}(x);};};autoc1=std::unordered_set<char>{};autoc2=std::unordered_set<long>{};autoc3=std::unordered_set<long,std::hash<int>>{};autoc4=std::unordered_set<long,Ha>{};std::cout<<"Max bucket count of\n"<<std::hex<<std::showbase<<"c1: "<<c1.max_bucket_count()<<'\n'<<"c2: "<<c2.max_bucket_count()<<'\n'<<"c3: "<<c3.max_bucket_count()<<'\n'<<"c4: "<<c4.max_bucket_count()<<'\n';}Possible output:
Max bucket count of c1: 0xfffffffffffffff c2: 0xfffffffffffffff c3: 0xfffffffffffffff c4: 0xaaaaaaaaaaaaaaa See also