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The combination of manual memory management and exceptions is particularly nasty. When you can't count on a GC to clean up for you every function has to be car

• evincarofautumn 15y ago
  Idiomatic C++ does not rely on manual memory management—it relies on deterministic memory management. Use unique_ptr, or shared_ptr when it makes sense (hint: it rarely does).
  • cageface 15y ago
    In theory you have every single leakable resource wrapped up in a RAII container or a smart pointer. In reality you're almost always dealing with raw pointers coming from a lower level C API or old C++ code or some kind of object handle you haven't wrapped yet. Of course the recommendation from Stroustrup & Sutter is to use the new smart pointers for everything but I think it will be a few years at least before most people can follow that advice.
    • ajross 15y ago
      Sure. And using deep-thrown (i.e. thrown across module/library boundaries -- often exceptions are local tricks used within tightly coupled code) exceptions in an application where you're dealing with such pointers would be bad design.
    • evincarofautumn 15y ago
      Typically what I do in that situation is lightly wrap the API. For instance: Image* image = allocate_image(…); … deallocate_image(image); ↓ struct ImageDeleter { void operator()(void* image) const { deallocate_image(image); } }; unique_ptr<Image, ImageDeleter> image(allocate_image(…)); That certainly can’t work everywhere, but I have yet to be failed by it.
      • jongraehl 15y ago
        People who don't do this are just asking for it.
        • malkia 15y ago
          That's a lot of boilerplate code. Okay there are macros to wrap such things, but I guess it's things like this that would make the future reader of the code puzzled.
          • cbsmith 15y ago
            jmq & basman provide examples of how to do it succinctly.
      • jmq 15y ago
        You can reduce verbosity of the code by passing destructor function directly to unique_ptr constructor: std::unique_ptr<Image, void (*)(Image *)>(image, deallocate_image);
        • evincarofautumn 15y ago
          Cool, thanks for the tip. I meant to offer an example for the general case.
      • basman 15y ago
        Or, perhaps easier: scoped_ptr<Image> image(allocate_image(...));