What does the following preprocessor directive do?

[contactsakthi]

Hi All,

What does the following pre-processor directive do?

#define X {{0xff, 0xffff}}

Thanks in advance

 

[Philip Potter]

Hi All,

What does the following pre-processor directive do?

#define X {{0xff, 0xffff}}

Thanks in advance

From this line forth until the end of translation unit or '#undef X',
every occurence of the indentifier X will be replaced with
{{0xff, 0xffff}}.

In other words, anywhere where you could have written {{0xff, 0xffff}}
you may now write X instead and it will have exactly the same effect.

For further reading, please refer to the pre-processor section of your C
textbook.

 

[Walter Roberson]

From this line forth until the end of translation unit or '#undef X',
every occurence of the indentifier X will be replaced with
{{0xff, 0xffff}}.

In other words, anywhere where you could have written {{0xff, 0xffff}}
you may now write X instead and it will have exactly the same effect.

Except in string or character literals, of course.