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I've got code that calls ::fgetpos, which results in a kernel exception that can't be caught (I have option /ehs in my VS 2008 project). But I can't help think that standard library routines should never throw these kinds of exceptions.

update: I've tried calling ::fgetpos(0, &foo), which is clearly wrong, and I indeed received a kernel-level exception. I'm baffled. Why would the C++ standard library not perform the most basic of argument checks (check for null-pointer) and raise a std::invalid_argument?

Do any standard library routines perform such basic checks, or do they all happily cause program termination?

Brent Arias
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  • What arguments are you passing to `fgetpos`? Standard Library functions can (often) do whatever they like if you provide invalid arguments. – James McNellis Feb 19 '11 at 20:46
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    Undefined behavior can do whatever it wants. I suspect when you call it, some invariant doesn't hold so your get your exception; not their fault you used the function wrong. – GManNickG Feb 19 '11 at 20:46

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Why would the C++ standard library not perform the most basic of argument checks (check for null-pointer)

Because you can do that yourself if you need the check. The philosophy of C++ is that you don't pay for what you don't need. If I'm a smart programmer and will never pass invalid arguments to the function, why should I have my program's performance potentially suffer with needless checks?

This is why std::vector, for example, provides both operator[] and at(), where the latter performs a bounds-check and the former doesn't. If you need the check, add it.

GManNickG
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