std::multimap<Key,T,Compare,Allocator>::merge
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|   template<class C2> void merge(std::map<Key, T, C2, Allocator>& source);  | 
(1) | (since C++17) | 
|   template<class C2> void merge(std::map<Key, T, C2, Allocator>&& source);  | 
(2) | (since C++17) | 
|   template<class C2> void merge(std::multimap<Key, T, C2, Allocator>& source);  | 
(3) | (since C++17) | 
|   template<class C2> void merge(std::multimap<Key, T, C2, Allocator>&& source);  | 
(4) | (since C++17) | 
Attempts to extract ("splice") each element in source and insert it into *this using the comparison object of *this.
No elements are copied or moved, only the internal pointers of the container nodes are repointed. All pointers and references to the transferred elements remain valid, but now refer into *this, not into source. 
The behavior is undefined if get_allocator() != source.get_allocator().
Parameters
| source | - | compatible container to transfer the nodes from | 
Return value
(none)
Exceptions
Does not throw unless comparison throws.
Complexity
N*log(size()+N)), where N is source.size()
Example
| This section is incomplete Reason: no example  | 
See also
|    (C++17)  | 
   extracts nodes from the container   (public member function)  | 
|    inserts elements or nodes (since C++17)  (public member function)  |