Determine if T meets the requirements of File.

Synopsis

Defined in header <boost/beast/core/file_base.hpp>

template<
    class T>
struct is_file :
    public std::integral_constant< bool,... >

Description

Metafunctions are used to perform compile time checking of template types. This type will be std::true_type if T meets the requirements, else the type will be std::false_type.

Example

Use with static_assert:

template<class File>
void f(File& file)
{
    static_assert(is_file<File>::value,
        "File type requirements not met");
...

Use with std::enable_if (SFINAE):

template<class File>
typename std::enable_if<is_file<File>::value>::type
f(File& file);