std::ranges::cdata - cppreference.com (original) (raw)

| Defined in header | | | | ----------------------------------------------------------------------------------------------------- | | ------------------------------------------ | | Defined in header | | | | inline namespace /*unspecified*/ { inline constexpr /*unspecified*/ cdata = /*unspecified*/; } | | (since C++20) (customization point object) | | Call signature | | | | template< class T > requires /* see below */ constexpr /* see below */ cdata( T&& t ); | | (since C++20) |

Returns a pointer to the first element of constant type(since C++23) of a contiguous range denoted by a const-qualified(until C++23) argument.

If ranges::cdata(t) is valid, then it returns a pointer to an object of constant type(since C++23).

Customization point objects

The name ranges::cdata denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.

[edit] Example

#include #include #include #include   int main() { std::string src {"hello world!\n"};   // std::ranges::cdata(src)[0] = 'H'; // error, src.data() is treated as read-only std::ranges::data(src)[0] = 'H'; // OK, src.data() is a non-const storage   char dst[20]; // storage for a C-style string std::strcpy(dst, std::ranges::cdata(src)); // [data(src), data(src) + size(src)] is guaranteed to be an NTBS   std::cout << dst; }

Output:

[edit] See also

| | obtains a pointer to the beginning of a contiguous range(customization point object)[edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | obtains the pointer to the underlying array (function template) [edit] |