The side effects
of an expression are its modifications to memory
and its accesses to volatile-qualified objects.
The side effects in the above expression
are the updating of
and any side effects contained within the functions f()
An expression's ``grouping'' is the way values are combined with other values and operators. The above expression's grouping is, primarily, the order in which the additions are performed.
includes everything necessary to produce its resulting value.
To evaluate an expression,
all specified side effects must occur
(anywhere between the previous and next sequence point)
and the specified operations are performed with a particular grouping.
For the above expression,
the updating of
must occur after the previous statement
and by the ``;''
of this expression statement;
the calls to the functions can occur in either order,
any time after the previous statement,
but before their return values are used.
note that the operators that cause memory to be updated
have no requirement to assign the new value before the
value of the operation is used.