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order of function arguments

setiz1 · 2009-09-11T10:18:07

Hi folks Are there any set order in which arguments to a function are executed? Shared_ptr's document says: === Avoid using unnamed shared_ptr temporaries to save typing; to see why this is dangerous, consider this example: void f(shared_ptr<int>, int); int g(); void ok() { shared_ptr<int> p(new int(2)); f(p, g()); } void bad() { f(shared_ptr<int>(new int(2)), g()); } The function ok follows the guideline to the letter, whereas bad constructs the temporary shared_ptr in place, admitting the possibility of a memory leak. Since function arguments are evaluated in unspecified order, it is possible for new int(2) to be evaluated first, g() second, and we may never get to the shared_ptr constructor if g throws an exception. See Herb Sutter's treatment (also here) of the issue for more information." === Particularly interesting was Herb Sutter's treatment which I read briefly just re-iterates NOT to use new within a function call (like the function bad( ) above). However, going through TICPP code on auto_ptr, there's a section on description of auto_ptr such: auto_ptr<TraceHeap> pMyObject(new TraceHeap(5),2); //I added the second argument for the sake of discussion (1) Now if and only if allocation of TraceHeap(5) fails (and subsequent exception raised, wouldn't that imply that the second argument "2" is never called? i.e., its arbritrary and possibly dangerous to use (1) above? Thanks folks! :-)