std::map, pointer to map key value, is this possible?

Question

std::map<std::string, std::string> myMap;  std::map<std::string, std::string>::iterator i = m_myMap.find(some_key_string); if(i == m_imagesMap.end())     return NULL;  string *p = &i->first; 

Is the last line valid? I want to store this pointer p somewhere else, will it be valid for the whole program life? But what will happen if I add some more elements to this map (with other unique keys) or remove some other keys, won’t it reallocate this string (key-value pair), so the p will become invalid?

Answer 1

Section 23.1.2#8 (associative container requirements):

The insert members shall not affect the validity of iterators and references to the container, and the erase members shall invalidate only iterators and references to the erased elements.

So yes storing pointers to data members of a map element is guaranteed to be valid, unless you remove that element.