Question

hello everyone I found this function in Kernel of the Linux:

inline task_t *context_switch(task_t *prev, task_t *next) {
...

switch_to(prev, next, prev);
return prev;
}

this function is making context switch, my question is why this function should be inline and not macro for example, thanks in advance…

Answer 1

It may not be a macro because a macro to do this would evaluate prev and next twice each, when they may be expressions with side effects. Also, after some searching I found that switch_to is (on some platforms) a macro that is a statement in braces, and therefore cannot return a value to be used in an expression.

I found some of this info here: https://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:task_switching