order of operations

[pauldepstein]

Assuming variables and functions have been defined correctly and x is
an int, is it unambiguous to write

x = f(x) + g(x);

Or does this lead to the possibility that the compiler will do x =
f(x) and then substitute that f(x) value into g(x)?

Thanks,

Paul Epstein

 

[kwikius]

* (e-mail address removed):

It's unambigious if neither function has side-effects.

However, if there are side-effects, then it becomes relevant that the
order of evaluation is unspecified.

What happens if both f(x) and g(x) are executed in parallel? Is that allowed
by the C++ standard?

regards
Andy Little

 

[James Kanze]

messagenews:[email protected]...

What happens if both f(x) and g(x) are executed in parallel?
Is that allowed by the C++ standard?

Only if the compiler can determine that it doesn't matter. A
function call is a sequence point, and you can't continue with
the rest of the calling expression (including, in this case,
calling g(x)) until the function returns. Modulo the "as if"
rule.