C++ FAQ / Section 4 / FAQ 4.6

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Revised Jul 4, 2012

[4.6] What updates were made for the 08/10 release?

Generic changes:

• Reverted the document's name back to its original name: C++ FAQ. Reason: the "Lite" suffix was an anachronism. The document has grown to 531 FAQs in 40 chapters/sections with well over 13,000 internal cross-references. It is far from "lite."
• Started some much-needed revamping of the templates section. That still needs a lot of work, and I welcome any additions. There are lots of topics that should be added!!
• As always, I am soliciting your additions for any section, templates or otherwise. Please send them in!

13 New FAQs:

• [2.5] Where can I find the C++ FAQ translated into Bulgarian?
  (created with much thanks to translator Anthony (Antoni) Ivanov)
• [2.13] Where can I find the C++ FAQ translated into Romanian?
  (created with much thanks to translator Emil Cataranciuc)
• [4.6] What updates were made for the 08/10 release?
  (created)
• [6.19] How can I help make the C++ FAQ even better??!??
  (created to coalesce all the "please help" messages that have traditionally been scattered throughout the FAQ)
• [10.10] What about returning a local variable by value? Does the local exist as a separate object, or does it get optimized away?
  (split this from [10.9] and rewrote to clarify the message)
• [10.13] Can I add = initializer; to the declaration of a class-scope static const data member?
  (created thanks to a suggestion from Chris Parker)
• [17.2] I'm still not convinced: a 4-line code snippet shows that return-codes aren't any worse than exceptions; why should I therefore use exceptions on an application that is orders of magnitude larger?
  (created)
• [17.3] How do exceptions simplify my function return type and parameter types?
  (created)
• [17.4] What does it mean that exceptions separate the "good path" (or "happy path") from the "bad path"?
  (created)
• [17.5] Okay, so you're saying exception handling is easy and simple, right?
  (created)
• [35.21] How can I create a container-template that allows my users to supply the type of the underlying container that actually stores the values?
  (created thanks to Victor Bazarov)
• [35.22] Follow-up to previous: can I pass in the underlying structure and the element-type separately?
  (created thanks to Victor Bazarov)
• [35.23] Related: all those proxies must negatively reflect on the speed of my program. Don't they?
  (created thanks to Victor Bazarov)

28 Changed FAQs:

• [1.3] Copying Permissions
  (wordsmithing)
• [2.1] Where's the closest mirror site to access this document?
  (updated the URL for the all-in-one compiled-help-file version thanks to Omar Lawand Dalatieh)
• [3.2] Is there a big difference between this on-line C++ FAQ and the C++ FAQ Book?
  (rewrote and updated)
• [5.3] What should I do if I see someone else posting a homework problem?
  (fixed typo thanks to Sergio Perez Camacho)
• [5.13] What about spam?
  (updated the URL thanks to Daniel Krügler)
• [10.9] Does return-by-value mean extra copies and extra overhead?
  (rewrote to clarify the message thanks to Nikola Smiljanic, and split the return-local-variable-by-value information into a separate FAQ)
• [10.11] Why can't I initialize my static member data in my constructor's initialization list?
  (added material showing why some static data member definitions don't have a "= initializer" part)
• [10.12] Why are classes with static data members getting linker errors?
  (added material regarding static const data members with initializer)
• [17.6] Exception handling seems to make my life more difficult; clearly I'm not the problem, am I??
  (reorganized the section, moving this FAQ up toward the beginning)
• [17.7] I have too many try blocks; what can I do about it?
  (reorganized the section, moving this FAQ up toward the beginning)
• [18.17] Why am I getting an error converting a Foo** → Foo const**?
  (added a cross-reference to the FAQ about converting Derived** to Base** thanks to a suggestion from Miloslavskiy Alexander)
• [20.7] When should my destructor be virtual?
  (clarified the wording of the virtual-destructor rule thanks to Nikola Smiljanic)
• [21.2] Converting Derived* → Base* works OK; why doesn't Derived** → Base** work?
  (added a cross-reference to the FAQ about converting Foo** to Foo const** thanks to a suggestion from Miloslavskiy Alexander)
• [23.4] When should someone use private virtuals?
  (coalesced duplicate definition of myOp() thanks to alert readers Nikola Smiljanic and Antoine W. Campagna)
• [25.6] Is there a simple way to visualize all these tradeoffs?
  (fixed a typo in the text thanks to Nikola Smiljanic)
• [25.9] Where in a hierarchy should I use virtual inheritance?
  (fixed a typo thanks to Miloslavskiy Alexander)
• [31.7] Sounds like I should never use reference semantics, right?
  (fixed a typo thanks to Miloslavskiy Alexander)
• [32.8] How can I pass an object of a C++ class to/from a C function?
  (rewrote prose to clarify issues surrounding different binary representations for Base* and Derived*)
• [33.8] How do I declare a pointer-to-member-function that points to a const member function?
  (fixed a typo in the code thanks to alert readers James Lingard, Stephen Howe and Andrew Denner)
• [33.10] Can I convert a pointer-to-member-function to a void*?
  (added technical details and rationale for why this sort of comparison is illegal thanks to a suggestion from Miloslavskiy Alexander)
• [33.11] Can I convert a pointer-to-function to a void*?
  (added technical details and rationale for why this sort of comparison is illegal thanks to a suggestion from Miloslavskiy Alexander)
• [34.5] How can I insert/access/change elements from a linked list/hashtable/etc?
  (fixed a typo in the text thanks to Nikola Smiljanic)
• [34.6] Can I have a container of smart pointers to my objects?
  (fixed a bug in the code thanks to Nikola Smiljanic and Miloslavskiy Alexander)
• [35.2] What's the syntax / semantics for a "class template"?
  (moved one of the method template definitions outside the class template body to show how that's done thanks to a suggestion from John Dickson)
• [35.14] How does the C++ keyword export help with template linker errors? Updated!
  (rewrote because the C++11 committee has voted export out of the standard, thanks to alert reader Alex Dumov)
• [36.2] How do I select the best serialization technique?
  (fixed a typo in the text thanks to Nikola Smiljanic)
• [36.4] How do I serialize/unserialize simple types like numbers, characters, strings, etc.?
  (fixed a typo in the FAQ title thanks to Nikola Smiljanic)
• [36.8] How do I serialize objects that are part of an inheritance hierarchy and that don't contain pointers to other objects?
  (added technical details and rationale for why unique[className] = unique.size() could cause an error thanks to a suggestion from Miloslavskiy Alexander)