std::source_location::function_name

 

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std::source_location

Member functions

Creation

source_location::source_location

source_location::current

Field Access

source_location::line

source_location::column

source_location::file_name

source_location::function_name

 

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)