Thestd::source_location class represents certain information about the source code, such as file names, line numbers, and function names. Previously, functions that desire to obtain this information about the call site (for logging, testing, or debugging purposes) must use macros so thatpredefined macros like__LINE__ and__FILE__ are expanded in the context of the caller. Thestd::source_location class provides a better alternative.

std::source_location meets theDefaultConstructible,CopyConstructible,CopyAssignable,Destructible andSwappable requirements.

Additionally, the following conditions aretrue:

• std::is_nothrow_move_constructible_v<std::source_location>,
• std::is_nothrow_move_assignable_v<std::source_location>, and
• std::is_nothrow_swappable_v<std::source_location>.

It is intended thatstd::source_location has a small size and can be copied efficiently.

It is unspecified whether the copy/move constructors and the copy/move assignment operators ofstd::source_location are trivial and/or constexpr.

[edit]Member functions

[edit]Notes

[edit]Example

#include <iostream>#include <source_location>#include <string_view> void log(conststd::string_view message,const std::source_location location=               std::source_location::current()){std::clog<<"file: "<< location.file_name()<<'('<< location.line()<<':'<< location.column()<<") `"<< location.function_name()<<"`: "<< message<<'\n';} template<typename T>void fun(T x){    log(x);// line 20} int main(int,char*[]){    log("Hello world!");// line 25    fun("Hello C++20!");}

file: main.cpp(25:8) `int main(int, char**)`: Hello world!file: main.cpp(20:8) `void fun(T) [with T = const char*]`: Hello C++20!

[edit]See also

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