Multi-line #define bitwise OR

Question

I'm trying to implement a #define as below:

#define CTRL_EVENT EVT_0 | EVT_1 | EVT_2 | EVT_3 | EVT_4 | EVT_5 | EVT_6 | EVT_7 | EVT_8 | EVT_9 

But in practice the #define will be even longer so I want to be able to split this line across multiple lines for readability purposes, is there a way of doing this?

Answer 1

A backslash immediately before a newline character acts as a line continuation. So you can do this:

#define CTRL_EVENT \
    (EVT_0 | EVT_1 | EVT_2 | EVT_3 | \
     EVT_4 | EVT_5 | EVT_6 | EVT_7 | \
     EVT_8 | EVT_9)

Also note the parenthesis which prevent unexpected operator grouping in larger expressions.