Insert value if its key is not already present.
Insert the specified value into this unordered map if the key (the first element) of the object referred to by value does not already exist in this unordered map; otherwise, this method has no effect (a value_type object having the key equivalent to the key of value already exists in this unordered map). Return a pair whose first member is an iterator referring to the (possibly newly inserted) value_type object in this unordered map whose key is equivalent to that of the object to be inserted, and whose second member is true if a new value was inserted, and false if a value having an equivalent key was already present. Note that this method requires that the (template parameter) types KEY and VALUE both be copy-insertable into this unordered map (see {Requirements on value_type}).
iterator to the element and whether insertion occurred
| Name | Description |
|---|---|
| value | value to insert |