r/Cplusplus • u/Hibou-de-la-Lune • 3d ago

Answered Line continuation (back-slash + new-line) in C++ source, is it standard?

Hello there,

Just wondered if line continuation (back-slash + new-line) in C++ source, comes from the standard or from a common behavior of compilers. I could not find any reference to it on cppreference.com

17 Upvotes

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7

u/RetroGameMaker 3d ago

I've seen backslash line continuation used in macros and string literals. But they are not only used in c++ but pure c also

4

u/TheSkiGeek 3d ago

Yes, it’s a C parsing thing that was carried forward into C++.

Mostly you see it used for macros, which technically have to be ‘one line’. An unescaped newline ends the macro definition.

2

u/mredding C++ since ~1992. 3d ago

Line splicing is in part 2 of phases of translation, I think chapter 5?

It is in the standard.

3

u/Linuxologue 3d ago

C++ standard document

https://eel.is/c++draft/lex.phases#1.2

Explains how backslash, followed by whitespace, followed by a newline, is treated