NAME¶

std::source_location::function_name - std::source_location::function_name

Synopsis¶

constexpr const char* function_name() const noexcept; (since C++20)

Returns the name of the function associated with the position represented by this
object, if any.

Parameters¶

(none)

Return value¶

If this object represents a position in a body of a function, returns an
implementation-defined null-terminated byte string corresponding to the name of the
function.

Otherwise, an empty string is returned.

Example¶

std::source_location::function_name may help to obtain the names of functions
(including the special functions) alongside with their signatures.

// Run this code

#include <cstdio>
#include <utility>
#include <source_location>

inline void print_function_name(
const std::source_location& location = std::source_location::current())
{
std::puts(location.function_name()); // prints the name of the caller
}

void foo(double &&) { print_function_name(); }

namespace bar { void baz() { print_function_name(); } }

template <typename T> auto pub(T) { print_function_name(); return 42; }

struct S {
S() { print_function_name(); }
S(int) { print_function_name(); }
~S() { print_function_name(); }
S& operator=(S const&) { print_function_name(); return *this; }
S& operator=(S&&) { print_function_name(); return *this; }
};

int main(int, char const* const[])
{
print_function_name();
foo(3.14);
bar::baz();
pub(0xFULL);
S p;
S q{42};
p = q;
p = std::move(q);
[] { print_function_name(); }();
}

Possible output:¶

int main(int, const char* const*)
void foo(double&&)
void bar::baz()
auto pub(T) [with T = long long unsigned int]
S::S()
S::S(int)
S& S::operator=(const S&)
S& S::operator=(S&&)
main(int, const char* const*)::<lambda()>
S::~S()
S::~S()

See also¶

line return the line number represented by this object
(public member function)
column return the column number represented by this object
(public member function)
file_name return the file name represented by this object
(public member function)