NAME

std::source_location::line - std::source_location::line

Synopsis

constexpr std::uint_least32_t line() const noexcept; (since C++20)

Returns the line number represented by this object.

Parameters

(none)

Return value

The line number represented by this object.

An implementation is encouraged to return 0 when the line number is unknown.

Example

// Run this code

#include <iostream>
#include <string_view>
#include <source_location>

inline void cur_line(
const std::string_view message = "",
const std::source_location& location = std::source_location::current())
{
std::cout
<< location.line() // <- the line # of a call site
<< ") "
<< message;
}

int main()
{
cur_line("++\n");
cur_line(); std::cout << "Hello,\n";
cur_line(); std::cout << "C++20!\n";
cur_line("--\n");
}

Output:

17) ++
18) Hello,
19) C++20!
20) --

See also

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)
function_name return the name of the function represented by this object, if any
(public member function)
source_line gets the line number that lexically relates the evaluation represented
(C++23) by the stacktrace_entry
(public member function of std::stacktrace_entry)
Filename and line information