__attribute __（（____ aligned __（PAGE_SIZE）））是什么意思？

Question

I am dealing with a Linux device driver project, in that i encountered with this:

__attribute__((aligned(PAGE_SIZE)))

I Think the above one is a specific use of __attribute__ .

I couldn't find satisfactory answers. I need to know, What does __attribute__ means, and the use of the same

Answer 1

It is used to specify that a variable or a struct should have a specific alignment in memory. Read about it here .

Basically in your example it forces whatever has that attribute to be aligned to a memory page ( PAGE_SIZE is just a numeric constant). The __attribute__ keyword is used to specify certain special things, aligned is just one of many.