std::ranges::common_range

Since C++20

Header: <ranges>

The common_range concept is a refinement of range for which std::ranges::begin() and std::ranges::end() return the same type (e.g. all standard library containers).

# Declarations

template< class T >
concept common_range =
ranges::range<T> && std::same_as<ranges::iterator_t<T>, ranges::sentinel_t<T>>;

(since C++20)

# Example

#include <ranges>
 
struct A
{
    char* begin();
    char* end();
};
static_assert( std::ranges::common_range<A> );
 
struct B
{
    char* begin();
    bool end();
};  // not a common_range: begin/end have different types
static_assert( not std::ranges::common_range<B> );
 
struct C
{
    char* begin();
};  // not a common_range, not even a range: has no end()
static_assert( not std::ranges::common_range<C> );
 
int main() {}

# See also