Defined in header <locale> template< class CharT > class ctype; Class ctype encapsulates character classification features. All stream input operations performed through std::basic_istream<charT> use the std::ctype<charT> of the locale imbued in the stream to identify whitespace characters for input tokenization. Stream output operations apply std::ctype<charT>::widen() to narrow-character arguments prior to output. Inheritance diagram. Two sta

constexpr piecewise_construct_t piecewise_construct = std::piecewise_construct_t(); (since C++11) The constant std::piecewise_construct is an instance of an empty struct tag type std::piecewise_construct_t. Example #include <iostream> #include <utility> #include <tuple> struct Foo { Foo(std::tuple<int, float>) { std::cout << "Constructed a Foo from a tuple\n"; } Foo(int, float) { std::cout << "Constructed a

(1) explicit unordered_multimap( size_type bucket_count = /*implementation-defined*/, const Hash& hash = Hash(), const KeyEqual& equal = KeyEqual(), const Allocator& alloc = Allocator() ); (since C++11) (until C++14) unordered_multimap() : unordered_multimap( size_type(/*implementation-defined*/) {} explicit unordered_multimap( size_type bucket_count, const Has

Classes and structs are user-defined types, defined by class-specifier, which appears in decl-specifier-seq of the declaration syntax. The class specifier has the following syntax: class-key attr class-head-name base-clause { member-specification } class-key - one of class or struct. The keywords are identical except for the default member access and the default base class access. attr(C++11) - optional sequence of any number of attributes, may include alignas specifier c

template< class Clock, class Duration > std::future_status wait_until( const std::chrono::time_point<Clock,Duration>& timeout_time ) const; (since C++11) wait_until waits for a result to become available. It blocks until specified timeout_time has been reached or the result becomes available, whichever comes first. The return value indicates why wait_until returned. The behavior is undefined if valid()== false before the call to this function. Parameters timeout_time

Defined in header <cstdlib> float strtof( const char* str, char** str_end ); (since C++11) double strtod( const char* str, char** str_end ); long double strtold( const char* str, char** str_end ); (since C++11) Interprets a floating point value in a byte string pointed to by str. Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to f

Queries size of the object or type. Used when actual size of the object must be known. Syntax sizeof( type ) (1) sizeof expression (2) Both versions return a constant of type std::size_t. Explanation 1) returns size in bytes of the object representation of type. 2) returns size in bytes of the object representation of the type, that would be returned by expression, if evaluated. Notes Depending on the computer architecture, a byte may consist of 8 or more bits, the exact

Defined in header <locale> template<class Codecvt, class Elem = wchar_t, class Tr = std::char_traits<Elem> > class wbuffer_convert : public std::basic_streambuf<Elem, Tr> (since C++11) std::wbuffer_convert is a wrapper over stream buffer of type std::basic_streambuf<char> which gives it the appearance of std::basic_streambuf<Elem>. All I/O performed through std::wbuffer_convert undergoes character conversion as defined by the

Defined in header <locale> byte_string to_bytes( Elem wchar ); (1) byte_string to_bytes( const Elem* wptr ); (2) byte_string to_bytes( const wide_string& wstr ); (3) byte_string to_bytes( const Elem* first, const Elem* last); (4) Performs wide to multibyte conversion, using the codecvt facet supplied at construction. 1) Converts wchar as if it was a string of length 1, to byte_string. 2) Converts the null-terminated wide character sequence beginning

static int xalloc(); Returns a unique (program-wide) index value that can be used to access one long and one void* elements in the private storage of std::ios_base by calling iword() and pword(). The call to xalloc does not allocate memory. This function is thread-safe; concurrent access by multiple threads does not result in a data race. (since C++14). Effectively increments a private static data member of std::ios_base, as if by executing return index++;, if index is the name of that