C++ Library -

The header in C++20, is designed to capture information about the source code at runtime. It provides a detailed information about the location of your code, such as the file name, line number without explicitly passing this information. It is particularly useful in the scenarios like debugging, logging and error-handling.

Before the introduction of the file names or line numbers are manually passed to logs or error handlers using the macros like __FILE__and__LINE__.

Including Header

To include the header in your C++ program, you can use the following syntax.

#include 

Functions of Header

Below is list of all functions from header.

Getting Function Name

In the following example, we are going to invoke the source_location::current() and retrieve the function name.

#include 
#include 
void x(const std::source_location & loc = std::source_location::current()) {
   std::cout << "Result : " << loc.function_name() << '\n';
}
void y() {
   x();
}
int main() {
   y();
}

Output

Output of the above code is as follows −

Result : void y()

Combining Multiple Source Location

Consider the following example, where we are going to combine the column number, line number into one log message.

#include 
#include 
void a(const std::string & message,
   const std::source_location & location = std::source_location::current()) {
   std::cout << "Message: " << message << "\n";
   std::cout << "Line: " << location.line() << "\n";
   std::cout << "Column: " << location.column() << "\n";
}
int main() {
   a("WELCOME");
   return 0;
}

Output

Following is the output of the above code −

Message: WELCOME
Line: 10
Column: 6