std::source_location::line

 

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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 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 (C++23)	gets the line number that lexically relates the evaluation represented by the stacktrace_entry (public member function of std::stacktrace_entry)
Filename and line information