std::meta::template_arguments_of

consteval std::vector<std::meta::info> template_arguments_of( std::meta::info r );

Returns a vector containing reflections of the template arguments used to instantiate the entity represented by r, in the order in which they appear in the template argument list.

For a given template argument A, the corresponding reflection value R is determined as follows:

• If A is a type or type alias, R represents the type.
• Otherwise, if A is a class template, variable template, concept, or alias template, R represents the template.
• Otherwise (A is a non-type template argument), let P be the corresponding template parameter.
• If P has reference type, R represents the object or function referred to by A.
• If P has class type, R represents the corresponding template parameter object.
• Otherwise, R represents the value of A.

Parameters

Return value

A vector containing reflections of the template arguments of what r represents.

Exceptions

Throws std::meta::exception unless std::meta::has_template_arguments(r) is true (i.e. r represents an entity instantiated from a template).

Example

#include <meta>
#include <type_traits>

static_assert(template_arguments_of(^^std::void_t<int>)[0] == ^^int);
static_assert(template_arguments_of(^^std::enable_if<true>).size() == 2);
static_assert(template_arguments_of(^^std::enable_if<true>)[0] ==
              std::meta::reflect_constant(true));
static_assert(template_arguments_of(^^std::enable_if<true>)[1] == ^^void);

int main() {}

See also