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Unary function object class that defines the hash specialization for type_index.
The functional call returns a hash value based on the type referred to by the type_index object: A hash value is a value that depends solely on its argument, returning always the same value for the same argument (for a given program execution). The value returned shall have a small likelihood of being the same as the one returned for a different argument (with chances of collision approaching
This allows the use of type_index objects as keys for unordered containers (like unordered_set or unordered_map).
See hash for additional information.
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
<typeindex>
classes
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type_indexC++11
-
type_index
-
type_index::type_indexC++11
member functions
-
type_index::hash_codeC++11
-
type_index::nameC++11
-
type_index::operatorC++11
-
non-member specializations
-
hash<type_index>C++11
-
- Reference
- <typeindex>
- type_index
- hash<type_index>
class template specialization
<typeindex>
std::hash<type_index>
template <class T> struct hash; // unspecializedtemplate <> struct hash <type_index>; // type_index
Hash for type_index
The functional call returns a hash value based on the type referred to by the type_index object: A hash value is a value that depends solely on its argument, returning always the same value for the same argument (for a given program execution). The value returned shall have a small likelihood of being the same as the one returned for a different argument (with chances of collision approaching
1/numeric_limits<size_t>::max).This allows the use of type_index objects as keys for unordered containers (like unordered_set or unordered_map).
See hash for additional information.
Member functions
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Spotted an error? contact us