Rule 14.2 What is meant by assign"

[misra-c]

In the 1st clause what is meant by “assign a value to the loop counter”. May this “value” be an expression with side-effects?

Code:

int index;
for ( set_val(&index) ;  index < 10 ; index++) // Is this compliant if set_val assigns to index

Note: the 2nd and 3rd clauses explicitly refer to expressions and whether side-effects are permitted.