inline constexpr /* unspecified */ data = /* unspecified */;
Call signature
(since C++20)Returns a pointer to the first element of a contiguous range.
If T is an array type and std::remove_all_extents_t<std::remove_reference_t<T>> is incomplete, then the call to ranges::data is ill-formed, no diagnostic required.
If the argument is an lvalue or ranges::enable_borrowed_range<std::remove_cv_t<T>> is true, a call to ranges::data is expression-equivalent to:
In all other cases, a call to ranges::data is ill-formed, which can result in substitution failure when ranges::data(e) appears in the immediate context of a template instantiation.
The name ranges::data denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.
If the argument is an rvalue (i.e. T is an object type) and ranges::enable_borrowed_range<std::remove_cv_t<T>> is false, the call to ranges::data is ill-formed, which also results in substitution failure.
If ranges::data(e) is valid for an expression e, then it returns a pointer to an object.
The C++20 standard requires that if the underlying data function call returns a prvalue, the return value is move-constructed from the materialized temporary object. All implementations directly return the prvalue instead. The requirement is corrected by the post-C++20 proposal P0849R8 to match the implementations.
#include <cstring>
#include <iostream>
#include <ranges>
#include <string>
int main()
{
std::string s{"Hello world!\n"};
char a[20]; // storage for a C-style string
std::strcpy(a, std::ranges::data(s));
// [data(s), data(s) + size(s)] is guaranteed to be an NTBS
std::cout << a;
}
Output:
[edit] See also obtains a pointer to the beginning of a read-only contiguous rangeRetroSearch is an open source project built by @garambo | Open a GitHub Issue
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