Possible Duplicate:
order of evaluation of function parameters
Is it safe to use the following construction in C/C++?
f(g(), h());
where g() is expected to be evaluated first, then h().
Do all compilers show the same behavior on all architectures?
NO! There is no guarantee what order these are carried out in. Only that both g() and h() are carried out before f(). See this: http://www.gotw.ca/gotw/056.htm I think there's an updated C++11 version of that, I'll have a look.
Edit: C++11 version http://herbsutter.com/gotw/_102/
Edit 2: If you really want to know what specific compilers do, try this: http://www.agner.org/optimize/calling_conventions.pdf Section 7 (page 16) may be relevant, though it's a bit over my head, but for instance __cdecl calling convention means arguments are passed from right to left (at least stored that way), whereas for __fastcall "The first two DWORD or smaller arguments are passed in ECX and EDX registers; all other arguments are passed right to left." (http://msdn.microsoft.com/en-us/library/6xa169sk%28v=vs.71%29.aspx)
So it does vary for different compilers.
Much later edit: It turns out that for constructors using the initializer list syntax (curly braces {}), order of evaluation is guaranteed (even if it is a call to a constructor that does not take a std::initializer_list. See this question.