std::source_location::current

Since C++20

Constructs a new source_location object corresponding to the location of the call site.

# Declarations

static consteval source_location current() noexcept;

(since C++20)

# Return value

If current() is invoked directly (via a function call that names current()), it returns a source_location object with implementation-defined values representing the location of the call. The values should be affected by the #line preprocessor directive in the same manner as the predefined macros LINE and FILE.

# Notes

std::source_location::current typically requires compiler’s built-in implementation.

# Example

#include <source_location>
#include <iostream>
 
struct src_rec {
    std::source_location srcl = std::source_location::current();
    int dummy = 0;
 
    src_rec(std::source_location loc = std::source_location::current()) :
        srcl(loc)    // values of member refer to the location of the calling function
    {}
    src_rec(int i) : // values of member refer to this location
        dummy(i)
    {}
    src_rec(double)  // values of member refer to this location
    {}
};
 
std::source_location src_clone(std::source_location a = std::source_location::current())
{
    return a;
}
 
std::source_location src_make()
{
    std::source_location b = std::source_location::current();
    return b;
}
 
int main()
{
    src_rec srec0;
    src_rec srec1(0);
    src_rec srec2(0.0);
    auto s0 = std::source_location::current();
    auto s1 = src_clone(s0);
    auto s2 = src_clone();
    auto s3 = src_make();
 
    std::cout
        << srec0.srcl.line() << ' ' << srec0.srcl.function_name() << '\n'
        << srec1.srcl.line() << ' ' << srec1.srcl.function_name() << '\n'
        << srec2.srcl.line() << ' ' << srec2.srcl.function_name() << '\n'
        << s0.line() << ' ' << s0.function_name() << '\n'
        << s1.line() << ' ' << s1.function_name() << '\n'
        << s2.line() << ' ' << s2.function_name() << '\n'
        << s3.line() << ' ' << s3.function_name() << '\n';
}

# See also