[4] Recent changes to this document  Updated! 
(Part of C++ FAQ Lite, Copyright © 1991-2003, Marshall Cline, cline@parashift.com)

FAQs in section [4]:

• [4.1] What updates were made for the 05/03 release?  New! 
• [4.2] What updates were made for the 04/03 release?  New! 
• [4.3] What updates were made for the 03/03 release?
• [4.4] What updates were made for the 02/03 release?
• [4.5] What updates were made for the 01/03 release?
• [4.6] What updates were made for the 12/02 release?
• [4.7] What updates were made for the 09/02 release?
• [4.8] What updates were made for the 06/02 release?
• [4.9] What updates were made for the 05/02 release?
• [4.10] What updates were made for the 04/02 release?
• [4.11] What updates were made for the 03/02 release?
• [4.12] What updates were made for the 08/01 release?
• [4.13] What updates were made for the 04/01 release?
• [4.14] What updates were made for the 07/00 release?
• [4.15] What updates were made for the 03/00 release?
• [4.16] What updates were made for the 01/00 release?
• [4.17] What updates were made for the 10/99 release?
• [4.18] What updates were made for the 07/99 release?
• [4.19] What updates were made for the 06/98 release?
• [4.20] What updates were made for the 05/98 release?
• [4.21] What updates were made for the 09/97 release?
• [4.22] What updates were made for the 01/97 release?
• [4.23] What updates were made for the 11/96 release?
• [4.24] What updates were made for the 10/96 release?
• [4.25] What updates were made for the 09/96 release?
• [4.26] What updates were made for the 08/96 release?
• [4.27] What updates were made for the 07/96 release?
• [4.28] What updates were made for the 06/96 release?
• [4.29] What updates were made for the 05/96 release?
• [4.30] What updates were made for the 04/96 release?
• [4.31] What updates were made for the 03/96 release?
• [4.32] What updates were made for the 09/95 release?
• [4.33] What updates were made for the 06/95 release?
• [4.34] What updates were made for the 04/95 release?
• [4.35] What updates were made for the 03/95 release?
• [4.36] What updates were made for the 01/95 release?
• [4.37] What updates were made for the 12/94 release?
• [4.38] What updates were made for the 11/94 release?
• [4.39] What updates were made for the 08/94 release?
• [4.40] What updates were made before 08/94?

1 New FAQs:

• [4.1] What updates were made for the 05/03 release?

5 Changed FAQs:

• [9.4] How can inline functions help with the tradeoff of safety vs. speed?
  (fixed a misspelling)
• [16.16] But the previous FAQ's code is SOOOO tricky and error prone! Isn't there a simpler way?
  (fixed a memory leak in the ctor when nrows or ncols was zero thanks to Chris Carton)
• [16.23] How do I provide reference counting with copy-on-write semantics for a hierarchy of classes?
  (fixed a subtle bug in the code thanks to James Megquier)
• [25.12] What special considerations do I need to know about when I inherit from a class that uses virtual inheritance?
  (fixed spelling error ("becuase") thanks to Olga Colombo)
• [36.4] Where can I get help on how to use STL?
  (added SGI's STL Programmer's guide)

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1 New FAQs:

• [4.2] What updates were made for the 04/03 release?

13 Changed FAQs:

• [3.1] Is there a C++ FAQ Book in addition to the C++ FAQ Lite?
  (rewrote, added several bookstores, and updated the URL for the source code)
• [7.5] How does C++ help with the tradeoff of safety vs. usability?
  (clarified that it is data declared as static at file-scope that is deprecated)
• [9.3] Do inline functions improve performance?
  (rewrote the "can cause thrashing" bullet thanks to Zarius Tularial; also reworded throughout to strengthen the points)
• [16.18] What's another way to build a Matrix template?
  (added methods nrows() and ncols() thanks to Christopher Mackie and Paolo Copello; inserted std:: in front of vector a few times thanks to Francisco Osorio G)
• [20.6] What is a "virtual constructor"?
  (added a note that MS VC++ 7.0 handles covariant return types thanks to Paolo Copello)
• [23.8] How can I set up my class so it won't be inherited from?
  (added the paragraph that the virtual inheritance approach might increase sizeof(Leaf))
• [26.6] I'm sooooo confused. Would you please go over the rules about bytes, chars, and characters one more time?
  (reworded the fifth bullet (so it doesn't use "effect") thanks to Mal Morrow and Chuck Pahlmeyer)
• [26.7] What is a "POD type"?
  (fixed a misspelling (equialent → equivalent) thanks to Mal Morrow)
• [34.3] Is the storage for a std::vector<T> guaranteed to be contiguous?
  (fixed a couple of typos in the last two paragraphs thanks to Dean Stanton)
• [36.2] Where can I get a copy of "STL"?
  (fixed the URL for the SGI implementation thanks to Jeremy Bishop)
• [37.2] Where can I get more information on using MFC and Visual C++?
  (rewrote with updated URLs thanks to Paolo Copello)
• [38.8] What are the C++ scoping rules for for loops?
  (replaced the pithy one-liner at the very beginning and corrected another typo thanks to Mans Gunnarsson)
• [39.3] Are there any pretty-printers that reformat C++ source code?
  (fixed the URL for C++2LaTeX thanks to Vinay Kumar Nallamothu)

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1 New FAQs:

• [4.3] What updates were made for the 03/03 release?

4 Changed FAQs:

• [5.9] Which newsgroup should I post my questions?
  (clarified that "the C++ language" means the language defined by the ISO/ANSI C++ Standard thanks to Victor Bazarov)
• [18.8] What does "Fred const& x" mean?
  (rewrote to make it even clearer that this is a business decision, and that the outcome will be different in different organizations)
• [18.9] What does "Fred const* x" mean?
  (rewrote to make it even clearer that this is a business decision, and that the outcome will be different in different organizations)
• [25.6] Is there a simple way to visualize all these tradeoffs?
  (fixed a typo ("calss" → "class") thanks to John Ericson)

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4 New FAQs:

• [4.4] What updates were made for the 02/03 release?
• [25.8] What is the "dreaded diamond"?
  (thanks to Carl Daniel)
• [25.9] Where in a hierarchy should I use virtual inheritance?
  (thanks to Carl Daniel)
• [25.10] What does it mean to "delegate to a sister class" via virtual inheritance?
  (thanks to Carl Daniel)

12 Changed FAQs:

• [5.1] What does IMHO mean? (or IMO, IMNSHO, FWIW, OTOH, etc.)?
  (added PEBCAC and PEBCAK thanks to William L. Thomson Jr.)
• [6.14] What does the FAQ mean by "such-in-such is evil"?
  (fixed a typo in second to last paragraph thanks to Joe Sewell)
• [15.3] How can I get std::cin to skip invalid input characters?
  (changed ignore()'s first parameter from int to std::streamsize thanks to Mike Wahler)
• [15.6] Why is my program ignoring my input request after the first iteration?
  (changed ignore()'s first parameter from int to std::streamsize thanks to Mike Wahler)
• [17.2] How can I handle a constructor that fails?
  (rewrote to make a stronger case against "zombie" objects)
• [18.15] Why am I getting an error converting a Foo** → const Foo**?
  (fixed a bug in the code (*q vs. *p) thanks to Richard van Wegen)
• [19.9] Okay, so exactly how should I decide whether to build a "protected interface"?
  (fixed a couple of typos thanks to Joe Sewell)
• [23.6] What's the meaning of, Warning: Derived::f(float) hides Base::f(int)?
  (added the last paragraph thanks to Carl Daniel)
• [23.8] How can I set up my class so it won't be inherited from?
  (added the virtual base class technique thanks to Carl Daniel)
• [25.11] What special considerations do I need to know about when I use virtual inheritance?
  (updated thanks to Carl Daniel)
• [25.12] What special considerations do I need to know about when I inherit from a class that uses virtual inheritance?
  (updated thanks to Carl Daniel)
• [33.2] How do I pass a pointer-to-member-function to a signal handler, X event callback, system call that starts a thread/task, etc?
  (fixed a typo in the name "The X Window System" thanks to Maurizio Colucci)

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9 New FAQs:

• [4.5] What updates were made for the 01/03 release?
• [15.3] How can I get std::cin to skip invalid input characters?
  (thanks to Mike Wahler and Sam Dutton)
• [18.9] What does "Fred const* x" mean?
• [18.15] Why am I getting an error converting a Foo** → const Foo**?
  (thanks to a question from Stephen Tashiro)
• [34.3] Is the storage for a std::vector<T> guaranteed to be contiguous?
  (thanks to Daveed Vandevoorde)
• [35.3] How do I decide whether to serialize to human-readable ("text") or non-human-readable ("binary") format?
• [35.4] How serialize/unserialize simple types like numbers, characters, strings, etc.?
• [35.5] How exactly do I read/write simple types in human-readable ("text") format?
• [35.6] How exactly do I read/write simple types in non-human-readable ("binary") format?
  (fixed a typo (indent vs. intent) and added a few clarifications thanks to Troy S)

16 Changed FAQs:

• [1.5] Trademarks
  (added comment about non-commercial sites being exempt from trademark dilution laws)
• [2.1] Where's the closest mirror site to access this document?
  (added URL to the mirror site in Israel thanks to Yechiel Kimchi)
• [6.15] Will I sometimes use any so-called "evil" constructs?
  (added "'Think' is not a four-letter word" thanks to Dave Power)
• [13.11] How can I overload the prefix and postfix forms of operators ++ and --?
  (fixed typo in title thanks to Kevin Goodsell)
• [18.8] What does "Fred const& x" mean?
  (added the paragraph starting "Note: you'll have to overcome a certain amount of inertia...")
• [21.2] Converting Derived* → Base* works OK; why doesn't Derived** → Base** work?
  (wordsmithed and clarified)
• [21.6] Is a Circle a kind-of an Ellipse?
  (strengthened the wording)
• [21.7] Are there other options to the "Circle is/isnot kind-of Ellipse" dilemma?
  (strengthened the wording)
• [21.8] But I have a Ph.D. in Mathematics, and I'm sure a Circle is a kind of an Ellipse! Does this mean Marshall Cline is stupid? Or that C++ is stupid? Or that OO is stupid?
  (strengthened the wording)
• [29.17] Why doesn't my floating-point comparison work?
  (clarified the code)
• [33.2] How do I pass a pointer-to-member-function to a signal handler, X event callback, system call that starts a thread/task, etc?
  (rewrote to discuss the (typical) void* parameter on many system- and GUI-calls thanks to Ryan Melville)
• [35.2] How do I select the best serialization technique?
  (fixed a misspelling ("forth" vs. "fourth") thanks to Charles Brockman; rewrote to include cross-references to the text/binary decision and how to handle simple types)
• [35.7] How do I serialize objects that aren't part of an inheritance hierarchy and that don't contain pointers to other objects?
  (added description of sample algorithm thanks to Niall Douglas; rewrote everything else as well)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (updated several links thanks to Thomas Tutone)
• [39.1] How can I generate HTML documentation for my classes? Does C++ have anything similar to javadoc?
  (added the link to PERCEPS)
• [39.3] Are there any pretty-printers that reformat C++ source code?
  (updated the URL for Source Styler)

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Big-picture changes:

• Added a new section on Multiple and Virtual Inheritance.
• Added a new section on Serialization.
• Added  New!  and  Updated!  tags on the section titles.

34 New FAQs:

• [4.6] What updates were made for the 12/02 release?
• [13.11] How can I overload the prefix and postfix forms of operators ++ and --?
  (thanks to Sandeep Grover)
• [13.12] Which is more efficient: i++ or ++i?
• [15.12] How can I open a stream in binary mode?
  (thanks to Simon Barner)
• [15.14] How can I write/read objects of my class to/from a data file?
• [15.15] How can I send objects of my class to another computer (e.g., via a socket, TCP/IP, FTP, email, a wireless link, etc.)?
• [19.8] I've been told to never use protected data, and instead to always use private data with protected access functions. Is that a good rule?
  (thanks to a question from Andrew Chan)
• [19.9] Okay, so exactly how should I decide whether to build a "protected interface"?
• [21.11] How could "it depend"??!? Aren't terms like "Circle" and "Ellipse" defined mathematically?
• [25.1] How is this section organized?
• [25.2] I've been told that I should never use multiple inheritance. Is that right?
• [25.3] So there are times when multiple inheritance isn't bad?!??
• [25.4] What are some disciplines for using multiple inheritance?
• [25.5] Can you provide an example that demonstrates the above guidelines?
• [25.6] Is there a simple way to visualize all these tradeoffs?
• [25.7] Can you give another example to illustrate the above disciplines?
• [25.11] What special considerations do I need to know about when I use virtual inheritance?
• [25.12] What special considerations do I need to know about when I inherit from a class that uses virtual inheritance?
• [25.13] What special considerations do I need to know about when I use a class that uses virtual inheritance?
• [25.14] One more time: what is the exact order of constructors in a multiple and/or virtual inheritance situation?
  (thanks to Carl Daniel)
• [33.7] Can I convert a pointer-to-member-function to a void*?
• [33.8] Can I convert a pointer-to-function to a void*?
• [34.13] How can I avoid linker errors with my template functions?
  (thanks to a suggestion by Michael Kochetkov)
• [34.14] How can I avoid linker errors with my template classes?
  (thanks to a suggestion by Michael Kochetkov)
• [35.1] What's this "serialization" thing all about?
  (thanks to a question from Stephen Tashiro)
• [35.2] How do I select the best serialization technique?
• [35.7] How do I serialize objects that aren't part of an inheritance hierarchy and that don't contain pointers to other objects?
• [35.8] How do I serialize objects that are part of an inheritance hierarchy and that don't contain pointers to other objects?
• [35.9] How do I serialize objects that contain pointers to other objects, but those pointers form a tree with no cycles and no joins?
• [35.10] How do I serialize objects that contain pointers to other objects, but those pointers form a tree with no cycles and only "trivial" joins?
• [35.11] How do I serialize objects that contain pointers to other objects, and those pointers form a graph that might have cycles or non-trivial joins?
  (thanks to a question from Stephen Tashiro)
• [35.12] Are there any caveats when serializing / unserializing objects?
• [35.13] What's all this about graphs, trees, nodes, cycles, joins, and joins at the leaves vs. internal nodes?
• [38.3] Can I templatize the above functions so they work with other types?
  (inspired by Merlyn Morgan-Graham)

20 Changed FAQs:

• [5.2] How do I get other people to do my homework problem for me?
  (added the "serious bodily harm" quote thanks to Jack Klein)
• [5.4] How can I find out about general netiquette so I don't embarrass myself?
  (added the joke/quote about top-posting)
• [6.14] What does the FAQ mean by "such-in-such is evil"?
  (fixed a typo in the last paragraph thanks to YaoJun)
• [10.15] Do I need to worry about the "static initialization order fiasco" for variables of built-in/intrinsic types?
  (added std:: prefix on cout thanks to Thomas Tutone)
• [13.1] What's the deal with operator overloading?
  (changed parameter types from by-value to by-reference-to-const)
• [15.13] How can I "reopen" std::cin and std::cout in binary mode?
  (removed references to DOS and OS/2)
• [15.16] Why can't I open a file in a different directory such as "..\test.dat"?
  (moved/renumbered)
• [29.3] Should I use void main() or int main()?
  (fixed parameter-order mistake thanks to Chris Young and many others)
• [29.17] Why doesn't my floating-point comparison work?
  (reworded)
• [33.2] How do I pass a pointer-to-member-function to a signal handler, X event callback, system call that starts a thread/task, etc?
  (shortened some names to make it easier to read)
• [33.5] How can I avoid syntax errors when calling a member function using a pointer-to-member-function?
  (renamed the macro to all-caps)
• [33.6] How do I create and use an array of pointer-to-member-function?
  (renamed the macro to all-caps)
• [34.12] Why can't I separate the definition of my templates class from it's declaration and put it inside a .cpp file?
  (added the caveat at the beginning; wordsmithed throughout)
• [36.4] Where can I get help on how to use STL?
  (added Rogue Wave's STL Guide thanks to Richard van Wegen)
• [36.8] Why is my executable so large?
  (added the paragraph on debugging thanks to Richard van Wegen; rewrote the second paragraph)
• [37.1] Where can I download a free C++ compiler?
  (added several new links thanks to Thomas Tutone)
• [38.1] How do I convert a value (a number, for example) to a std::string?
  (fixed a typo in the last paragraph thanks to Alex Rutchka, rewrote the code examples to use exceptions, and moved it from the I/O section)
• [38.2] How do I convert a std::string to a number?
  (rewrote the code examples to use exceptions, added the failIfLeftoverChars, and moved it from the I/O section)
• [38.4] What should be done with macros that contain if?
  (reworded in various spots)
• [38.5] What should be done with macros that have multiple lines?
  (reworded)

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Big-picture changes:

• Hyperlinks now have "hover text" — text that most browsers show when your mouse hovers over a hyperlink (though please don't write me if your particular browser doesn't have this feature; most browsers have it but some do not).
• Added a new mirror site in Poland.
• Made things easier to find by adding lots more index-terms to the permuted subject index.

9 New FAQs:

• [4.7] What updates were made for the 09/02 release?
• [6.15] Will I sometimes use any so-called "evil" constructs?
• [9.2] What's a simple example of procedural integration?
• [15.7] Should I end my output lines with std::endl or '\n'?
  (thanks to Moshe Shimoni)
• [15.20] How can I clear the screen? Is there something like clrscr()?
• [15.21] How can I change the colors on the screen?
• [23.4] Okay, but is there a way to simulate that behavior as if dynamic binding worked on the this object within my base class's constructor?
  (thanks to Alf Steinbach for inspiration, ideas, and constructive criticism)
• [29.3] Should I use void main() or int main()?
• [29.4] Should I use f(void) or f()?
  (thanks to a question from Mario Knezovic)

31 Changed FAQs:

• [2.5] Where can I download a Chinese translation of the C++ FAQ Lite?
  (updated the URL for the Big5 encoding)
• [5.1] What does IMHO mean? (or IMO, IMNSHO, FWIW, OTOH, etc.)?
  (added PMFJI)
• [5.4] How can I find out about general netiquette so I don't embarrass myself?
  (added admonitions against top-posting, HTML/rich-text postings, attachments, "C/C++," and confusing classes with objects; also removed "include a valid email address")
• [6.8] Are virtual functions (dynamic binding) central to OO/C++?
  (minor clarifications)
• [6.13] What are some "interview questions" I could ask that would let me know if candidates really know their stuff?
  (fixed a spelling error thanks to Martin Linklater)
• [9.1] What's the deal with inline functions?
  (rewrote, adding several new points)
• [9.3] Do inline functions improve performance?
  (rewrote, added numerous new points)
• [9.5] Why should I use inline functions instead of plain old #define macros?
  (wordsmithed)
• [10.3] Can one constructor of a class call another constructor of the same class to initialize the this object?
  (rewrote for clarification thanks to Nikolai Borissov)
• [10.4] Is the default constructor for Fred always Fred::Fred()?
  (partially rewrote for clarity)
• [11.6] What if I want a local to "die" before the close } of the scope in which it was created? Can I call a destructor on a local if I really want to?
  (wordsmithed)
• [17.4] How should I handle resources if my constructors may throw exceptions?
  (added the example and the admonition to use a typedef)
• [17.5] How do I change the string-length of an array of char to prevent memory leaks even if/when someone throws an exception?
  (rewrote to clarify/strengthen)
• [18.8] What does "Fred const& x" mean?
  (rewrote to address the "guru approach")
• [20.5] When should my destructor be virtual?
  (rewrote)
• [21.3] Is a parking-lot-of-Car a kind-of parking-lot-of-Vehicle?
  (strengthened in several places)
• [21.8] But I have a Ph.D. in Mathematics, and I'm sure a Circle is a kind of an Ellipse! Does this mean Marshall Cline is stupid? Or that C++ is stupid? Or that OO is stupid?
  (fixed typo in first paragraph thanks to Jim Fischer)
• [21.12] If SortedList has exactly the same public interface as List, is SortedList a kind-of List?
  (strengthened the wording in a few places)
• [23.3] When my base class's constructor calls a virtual function on its this object, why doesn't my derived class's override of that virtual function get invoked?
  (rewrote completely and added an example program)
• [23.5] Should a derived class redefine ("override") a member function that is non-virtual in a base class?
  (reworded the question — clarification)
• [23.6] What's the meaning of, Warning: Derived::f(float) hides Base::f(int)?
  (changed typo f(double) to f(float) thanks to Tarjei Knapstad)
• [26.9] When initializing static data members of built-in / intrinsic / primitive types, should I worry about the "static initialization order fiasco"?
  (reworded thanks to Orjan Petersson)
• [29.2] Where do I start? Why do I feel so confused, so stupid?
  (added sites for "sample problems")
• [29.16] Why is floating point so inaccurate? Why doesn't this print 0.43?
  (moved from the Miscellaneous Technical Issues section)
• [29.17] Why doesn't my floating-point comparison work?
  (added links to David Goldberg's paper and to Doug Priest's supplement thanks to Kevin Quitt; added a definition for isEqual(double,double) thanks to Steve Summit; moved from the Miscellaneous Technical Issues section)
• [32.5] How can I call a non-system C function f(int,char,float) from my C++ code?
  (changed "C code" to "C++ code" in the first sentence thanks to Sreenivas Sunil Penumarthy)
• [33.5] How can I avoid syntax errors when calling a member function using a pointer-to-member-function?
  (made it clearer there is an and between the recommended typedef and macro)
• [33.6] How do I create and use an array of pointer-to-member-function?
  (made it clearer there is an and between the recommended typedef and macro)
• [36.4] Where can I get help on how to use STL?
  (wordsmithed for clarity)
• [36.9] Where can I get tons and tons of more information on C++ class libraries?
  (added the "with frames" URL for the C++ Libraries FAQ and the comment about google, both thanks to Henrik Haraldsson)
• [39.1] How can I generate HTML documentation for my classes? Does C++ have anything similar to javadoc?
  (moved from the Miscellaneous Technical Issues section)

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Big-picture changes:

• Added a new section on Newbie Questions / Answers.

20 New FAQs:

• [4.8] What updates were made for the 06/02 release?
• [6.14] What does the FAQ mean by "such-in-such is evil"?
• [21.12] If SortedList has exactly the same public interface as List, is SortedList a kind-of List?
  (thanks to a conversation with Dave Mikesell)
• [26.12] How can I tell if an integer is a power of two without looping?
  (thanks to S.K. Mody)
• [29.1] What is this "newbie section" all about?
• [29.2] Where do I start? Why do I feel so confused, so stupid?
  (thanks to a question from John Lester)
• [29.5] What are the criteria for choosing between short / int / long data types?
  (thanks to a question from John Lester)
• [29.6] What the heck is a const variable? Isn't that a contradiction in terms?
  (thanks to a question from John Lester)
• [29.7] Why would I use a const variable / const identifier as opposed to #define?
  (thanks to a question from John Lester)
• [29.8] Are you saying that the preprocessor is evil?
• [29.9] What is the "standard library"? What is included / excluded from it?
  (thanks to a question from John Lester)
• [29.10] How should I lay out my code? When should I use spaces, tabs, and/or newlines in my code?
  (thanks to a question from John Lester)
• [29.11] Is it okay if a lot of numbers appear in my code?
• [29.12] What's the point of the L, U and f suffixes on numeric literals?
  (thanks to a question from John Lester)
• [29.13] I can understand the and (&&) and or (||) operators, but what's the purpose of the not (!) operator?
  (thanks to a question from John Lester)
• [29.14] Is !(a < b) logically the same as a >= b?
• [29.15] What is this NaN thing?
• [29.18] What is the type of an enumeration such as enum Color? Is it of type int?
  (thanks to a question from John Lester)
• [29.19] If an enumeration type is distinct from any other type, what good is it? What can you do with it?
  (thanks to a question from John Lester)
• [37.6] What's the difference between C++ and Visual C++?
  (based on a question from Lavanya Mahashankar)

13 Changed FAQs:

• [2.7] Where can I download a Portuguese translation of the C++ FAQ Lite?
  (updated the URL)
• [3.1] Is there a C++ FAQ Book in addition to the C++ FAQ Lite?
  (changed the URL for the book cover and excerpts thanks to Thomas Hansen; also added the sample chapter and source code.)
• [5.6] Wait a minute, does that previous FAQ say to not answer their question just because it's already answered in the FAQ?!?
  (fixed misspelling in "cripple" thanks to John Marshall plus general rewording)
• [5.13] What about spam?
  (fixed a typo thanks to Paul Savage)
• [10.6] Should my constructors use "initialization lists" or "assignment"?
  (added symmetry argument wrt non-static const members thanks to Tanmoy Bhattacharya)
• [10.13] Why doesn't the construct-on-first-use idiom use a static object instead of a static pointer?
  (made substantive changes to the second-to-last paragraph thanks to Amitha Perera and Wil Evers)
• [18.11] What do I do if I want a const member function to make an "invisible" change to a data member?
  (reworded the question to distinguish "invisible change" from "invisible data member" thanks to Thomas Hansen)
• [26.4] But, but, but what about machines where a char has more than 8 bits? Surely you're not saying a C++ byte might have more than 8 bits, are you?!?
  (removed a superfluous statement)
• [26.6] I'm sooooo confused. Would you please go over the rules about bytes, chars, and characters one more time?
  (rewrote; changed the example from the mythical FOO machine to a PDP-10, plus added words showing how to simulate pointers using software, much thanks to Andrew Koenig)
• [26.7] What is a "POD type"?
  (added note that POD types can contain non-virtual member functions thanks to Andrew Koenig)
• [26.8] When initializing non-static data members of built-in / intrinsic / primitive types, should I use the "initialization list" or assignment?
  (clarified the cross-reference)
• [26.9] When initializing static data members of built-in / intrinsic / primitive types, should I worry about the "static initialization order fiasco"?
  (made it clearer that the FAQ provides a solution)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (updated the link to KAI C++)

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Big-picture changes:

• Added a new section on built-in / intrinsic / primitive data types.
• Updated the link to the Portuguese translation.

16 New FAQs:

• [4.9] What updates were made for the 05/02 release?
• [5.6] Wait a minute, does that previous FAQ say to not answer their question just because it's already answered in the FAQ?!?
• [15.17] How can I tell {if a key, which key} was pressed before the user presses the ENTER key?
  (inspired by a posting by Alan Didey)
• [15.18] How can make it so keys pressed by users are not echoed on the screen?
• [15.19] How can I move the cursor around on the screen?
• [26.1] Can sizeof(char) be 2 on some machines? For example, what about double-byte characters?
  (inspired by Randy Sherman)
• [26.2] What are the units of sizeof?
  (inspired by Randy Sherman)
• [26.3] Whoa, but what about machines or compilers that support multibyte characters. Are you saying that a "character" and a char might be different?!?
  (inspired by Randy Sherman)
• [26.4] But, but, but what about machines where a char has more than 8 bits? Surely you're not saying a C++ byte might have more than 8 bits, are you?!?
  (thanks to Randy Sherman)
• [26.5] Okay, I could imagine a machine with 9-bit bytes. But surely not 16-bit bytes or 32-bit bytes, right?
  (thanks to Randy Sherman)
• [26.6] I'm sooooo confused. Would you please go over the rules about bytes, chars, and characters one more time?
  (thanks to Randy Sherman)
• [26.7] What is a "POD type"?
• [26.8] When initializing non-static data members of built-in / intrinsic / primitive types, should I use the "initialization list" or assignment?
• [26.9] When initializing static data members of built-in / intrinsic / primitive types, should I worry about the "static initialization order fiasco"?
• [26.10] Can I define an operator overload that works with built-in / intrinsic / primitive types?
• [26.11] When I delete an array of some built-in / intrinsic / primitive type, why can't I just say delete a instead of delete[] a?

5 Changed FAQs:

• [6.13] What are some "interview questions" I could ask that would let me know if candidates really know their stuff?
  (rewrote from scratch thanks to Robin)
• [7.6] How can I prevent other programmers from violating encapsulation by seeing the private parts of my class?
  (minor rewording)
• [11.14] Is there a way to force new to allocate memory from a specific memory area?
  (two typos ("myPool" vs. "pool") in the code were fixed thanks to Randy Sherman)
• [32.3] How can I include a non-system C header file in my C++ code?
  (fixed a grammatical error in the first paragraph thanks to Randy Sherman)
• [37.13] Is it possible to convert C++ to C?
  (added a URL for Cfront and reworded the third bullet)

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3 New FAQs:

• [4.10] What updates were made for the 04/02 release?
• [11.14] Is there a way to force new to allocate memory from a specific memory area?
  (inspired by a conversation with Tuan Tran)
• [27.13] Should I use "unusual" syntax?

4 Changed FAQs:

• [2.1] Where's the closest mirror site to access this document?
  (added URL to the mirror site in the Netherlands thanks to Almer Visser)
• [13.10] Should I design my classes from the outside (interfaces first) or from the inside (data first)?
  (rewrote the rationale for hiding nodes as inspired by a discussion with Michael Lacher)
• [27.12] Are there any other sources of coding standards?
  (added several new links and updated numerous changed URLs thanks to John Vorwald)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (updated URLs for Intel's and Watcom's C++ compilers, and added Open Watcom, thanks to Dave Symonds)

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Global changes:

• Changed the HTML "anchor" scheme so it conforms to the standard. Thanks to Eric Anderson for pointing this out.

4 New FAQs:

• [4.11] What updates were made for the 03/02 release?
• [6.13] What are some "interview questions" I could ask that would let me know if candidates really know their stuff?
  (thanks to inspiration from Shawn Panosian)
• [34.12] Why can't I separate the definition of my templates class from it's declaration and put it inside a .cpp file?
  (thanks to Assaf Lavie)
• [39.1] How can I generate HTML documentation for my classes? Does C++ have anything similar to javadoc?
  (thanks to Joe Linoff)

27 Changed FAQs:

• [3.1] Is there a C++ FAQ Book in addition to the C++ FAQ Lite?
  (changed the URL for book excerpts thanks to Chris Young)
• [5.1] What does IMHO mean? (or IMO, IMNSHO, FWIW, OTOH, etc.)?
  (added OO)
• [6.10] Is C++ backward compatible with ANSI/ISO C?
  (clarified the relationship between f() in C and f(...) in C++ thanks to Stefan Farfeleder)
• [6.12] Where can I get a copy of the ANSI/ISO C++ standard?
  (swapped some mixed up links thanks to Randal Leistikow)
• [8.7] What is a handle to an object? Is it a pointer? Is it a reference? Is it a pointer-to-a-pointer? What is it?
  (changed pointers-to-references into references-to-pointers thanks to Scott Douglass)
• [13.1] What's the deal with operator overloading?
  (added comment about templates and intrinsic types thanks to Phil Hibbs)
• [15.1] Why should I use <iostream> instead of the traditional <cstdio>?
  (corrected grammar of first bullet ("better type safety" ==> "more type-safe") thanks to Tristan Miller)
• [15.16] Why can't I open a file in a different directory such as "..\test.dat"?
  (added an explanation as to why "/" is better than "\\" thanks to Chris Young)
• [16.2] Can I free() pointers allocated with new? Can I delete pointers allocated with malloc()?
  (strengthened)
• [18.11] What do I do if I want a const member function to make an "invisible" change to a data member?
  (added a caveat about this being a const Set* const thanks to Steve White)
• [20.4] I have a heterogeneous list of objects, and my code needs to do class-specific things to the objects. Seems like this ought to use dynamic binding but can't figure it out. What should I do?
  (fixed typo in a typedef thanks to Salminen Kari; plus various clarifications throughout)
• [20.6] What is a "virtual constructor"?
  (added parenthetical recommendation about slicing thanks to Jesse Jones)
• [21.2] Converting Derived* → Base* works OK; why doesn't Derived** → Base** work?
  (added a paragraph near the end about using a pointer cast thanks to Steve White)
• [21.6] Is a Circle a kind-of an Ellipse?
  (reworded)
• [21.7] Are there other options to the "Circle is/isnot kind-of Ellipse" dilemma?
  (added words allowing Circle to be a state of Ellipse rather than a class in itself thanks to Nicholas Leippe)
• [21.8] But I have a Ph.D. in Mathematics, and I'm sure a Circle is a kind of an Ellipse! Does this mean Marshall Cline is stupid? Or that C++ is stupid? Or that OO is stupid?
  (softened things up in two spots (thanks to Salminen Kari and Nicholas Leippe) and made it even more in-your-face in other spots (blame the author for this second set of changes — I'm the meanie))
• [27.7] What source-file-name convention is best? foo.cpp? foo.C? foo.cc?
  (rewrote/wordsmithed thanks to Michael Tiller)
• [27.12] Are there any other sources of coding standards?
  (removed a dead link thanks to Phil Hibbs)
• [28.7] What are some best-of-breed C++ programming-by-example guides?
  (added Musser's STL book thanks to Xavier Outhier from D2SET scientific and technology non profit association)
• [29.17] Why doesn't my floating-point comparison work?
  (added new book references thanks to Alan McKenney)
• [36.2] Where can I get a copy of "STL"?
  (removed dead link to Musser's STL site thanks to Xavier Outhier from D2SET scientific and technology non profit association)
• [36.4] Where can I get help on how to use STL?
  (removed dead link to Musser's STL site thanks to Xavier Outhier from D2SET scientific and technology non profit association; added link to book section)
• [36.9] Where can I get tons and tons of more information on C++ class libraries?
  (added the URL to www.mathtools.net/C++/ thanks to Ophir Herbst; also added the boost.org URL)
• [37.1] Where can I download a free C++ compiler?
  (added Digital Mars to the list (thanks Walter!))
• [37.4] How can I decompile an executable program back into C++ source code?
  (added caveat at the end re legitimate reasons to decompile)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (removed Symantec C++ since Symantec's web site says it is "discontinued," thanks to Richard Gill; added an annotation that the Digital Mars compiler is free, thanks to Walter Bright; and added the URL to the Cygwin-compiled version of GCC, thanks to Wouter Demuynck)
• [39.3] Are there any pretty-printers that reformat C++ source code?
  (added "Source Styler for C++" thanks to Alison Boyce)

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New features:

• You can now search the C++ FAQ (thanks to www.google.com).
• The FAQ has now been translated into Chinese using the GB encoding (typically used on the Chinese mainland).

13 New FAQs:

• [4.12] What updates were made for the 08/01 release?
• [5.10] Should I post job advertisements and/or resumes on comp.lang.c++?
  (thanks to David Harmon and Brian B. Rodenborn)
• [5.11] What if I really need a job; should I post my resume on comp.lang.c++?
  (thanks to David Harmon and Brian B. Rodenborn)
• [5.12] What should I do to someone who posts something off-topic?
• [5.13] What about spam?
• [10.13] Why doesn't the construct-on-first-use idiom use a static object instead of a static pointer?
• [10.15] Do I need to worry about the "static initialization order fiasco" for variables of built-in/intrinsic types?
  (thanks to Cyril Schmidt)
• [20.4] I have a heterogeneous list of objects, and my code needs to do class-specific things to the objects. Seems like this ought to use dynamic binding but can't figure it out. What should I do?
  (based on an email discussion with Jeramie Hicks)
• [23.8] How can I set up my class so it won't be inherited from?
• [23.9] How can I set up my member function so it won't be overridden in a derived class?
• [27.10] Why do people worry so much about pointer casts and/or reference casts?
• [29.17] Why doesn't my floating-point comparison work?
  (thanks to Stan Brown)
• [37.13] Is it possible to convert C++ to C?
  (thanks to J. Stephen Adamczyk and Greg Comeau)

24 Changed FAQs:

• [2.1] Where's the closest mirror site to access this document?
  (removed the Finland mirror site — it wasn't being kept up-to-date)
• [2.5] Where can I download a Chinese translation of the C++ FAQ Lite?
  (added the URL for the GB-encoded version thanks to Shen Min for the translation)
• [10.6] Should my constructors use "initialization lists" or "assignment"?
  (reworded various things thanks to Stan Brown)
• [10.7] Should you use the this pointer in the constructor?
  (wordsmithed thanks to Stan Brown)
• [10.11] What's the "static initialization order fiasco"?
  (closed loophole wrt built-in/intrinsic types thanks to Cyril Schmidt)
• [10.12] How do I prevent the "static initialization order fiasco"?
  (closed loophole wrt built-in/intrinsic types thanks to Cyril Schmidt)
• [10.14] How do I prevent the "static initialization order fiasco" for my static data members?
  (closed loophole wrt built-in/intrinsic types thanks to Cyril Schmidt)
• [10.17] What is the "Named Parameter Idiom"?
  (wordsmithed and added last paragraph with inspiration from Stan Brown)
• [14.2] Do friends violate encapsulation?
  (added the last paragraph with inspiration from Stan Brown)
• [14.4] What does it mean that "friendship isn't inherited, transitive, or reciprocal"?
  (wordsmithed ("nor" vs. "or") thanks to Herbert Gintis)
• [16.5] Do I need to check for NULL after p = new Fred()?
  (changed endl to std::endl)
• [16.24] Can you absolutely prevent people from subverting the reference counting mechanism, and if so, should you?
  (wordsmithed thanks to Stan Brown)
• [16.25] Can I use a garbage collector in C++?
  (added cross-references thanks to Stan Brown)
• [16.26] What are the two kinds of garbage collectors for C++?
  (added a URL for Attardi and Flagella's CMM thanks to Markus Laker)
• [19.7] How can I protect derived classes from breaking when I change the internal parts of the base class?
  (wordsmithed thanks to Stan Brown)
• [20.6] What is a "virtual constructor"?
  (added the paragraph about MS VC++ 6.0's mishandling of Covariant Return Types; thanks to Karthik for pointing this out)
• [28.4] Should I buy one book, or several?
  (wordsmithed thanks to Stan Brown)
• [32.1] What do I need to know when mixing C and C++ code?
  (fixed a typo thanks to Kumaran Surrendra; added the paragraph on compiling everything, even C-style code, using a C++ compiler thanks to Gary Jenkins)
• [36.2] Where can I get a copy of "STL"?
  (added comment about "<string>" thanks to Stan Brown)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (added URL for Digital Mars C++ thanks to Walter Bright)
• [38.1] How do I convert a value (a number, for example) to a std::string?
  (changed <stdio> to <cstdio> thanks to Stan Brown)
• [38.2] How do I convert a std::string to a number?
  (changed <stdio> to <cstdio> thanks to Stan Brown)
• [38.6] What should be done with macros that need to paste two tokens together?
  (removed ambivalence regarding second layer of indirection when using ## thanks to Joshua Fraser and Ronald Fischer)
• [39.2] Is there a TeX or LaTeX macro that fixes the spacing on "C++"?
  (wordsmithed thanks to Stan Brown)

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Global changes:

• Updated the opening page so it lists both the chain of recent changes as well as the table of recent changes. This improvement is thanks to a suggestion by John Kewley.
• Moved the main FAQ site to www.parashift.com/c++-faq-lite/. (This was unfortunately necessary due to a business issue involving AT&T and the previous web hosting company, Cerf-Net.)

11 New FAQs:

• [2.8] Where can I download a Russian translation of the C++ FAQ Lite?
  (thanks to Yaroslav Mironov)
• [4.13] What updates were made for the 04/01 release?
• [8.4] What does object.method1().method2() mean?
  (thanks to Robert Cullen)
• [8.7] What is a handle to an object? Is it a pointer? Is it a reference? Is it a pointer-to-a-pointer? What is it?
• [10.17] What is the "Named Parameter Idiom"?
• [16.18] What's another way to build a Matrix template?
  (thanks to Jesper Rasmussen)
• [16.24] Can you absolutely prevent people from subverting the reference counting mechanism, and if so, should you?
• [23.1] Is it okay for a non-virtual function of the base class to call a virtual function?
• [23.2] That last FAQ confuses me. Is it a different strategy from the other ways to use virtual functions? What's going on?
• [28.7] What are some best-of-breed C++ programming-by-example guides?
• [34.9] How do I explicitly select which version of a function template should get called?
  (with help from Perry Rapp)

27 Changed FAQs:

• [5.2] How do I get other people to do my homework problem for me?
  (added stuff about the evils of asking others to do your homework for you via email)
• [6.12] Where can I get a copy of the ANSI/ISO C++ standard?
  (total rewrite; changed several URLs thanks to Brian K. Hamon and Garen Parham)
• [9.3] Do inline functions improve performance?
  (explained "code bloat" and also added lots of if's, and's and but's)
• [10.6] Should my constructors use "initialization lists" or "assignment"?
  (rewrote)
• [10.7] Should you use the this pointer in the constructor?
  (rewrote because of a suggestion from Perry Rapp)
• [10.9] Why can't I initialize my static member data in my constructor's initialization list?
  (added a "," in the initialization list thanks to Yaroslav Mironov)
• [14.2] Do friends violate encapsulation?
  (made a bit more emphatic)
• [14.4] What does it mean that "friendship isn't inherited, transitive, or reciprocal"?
  (added the "not reciprocal" item thanks to Karel Roose)
• [15.9] But shouldn't I always use a printOn() method rather than a friend function?
  (fixed a bug thanks to Richard Hector)
• [16.16] But the previous FAQ's code is SOOOO tricky and error prone! Isn't there a simpler way?
  (fixed the Star Trek movie number thanks to Chris Sheppard, wordsmithed last paragraph at the suggestion of Perry Rapp)
• [16.21] How do I do simple reference counting?
  (moved definition of Fred::create() methods below the definition of class FredPtr)
• [16.26] What are the two kinds of garbage collectors for C++?
  (added a URL for Bartlett's collector thanks to Abhishek)
• [17.2] How can I handle a constructor that fails?
  (fixed typo ("its" vs. "it's") thanks to Wes Bemont)
• [24.2] How are "private inheritance" and "composition" similar?
  (changed the syntax to using Engine::start; and added the sixth distinction thanks to Stan Brown; added the third similarity; added "aggregation" as another synonym; wordsmithed various parts)
• [27.1] What are some good C++ coding standards?
  (fixed typo changing "where" to "were" thanks to Robert Marshall)
• [27.11] Which is better: identifier names that_look_like_this or identifier names thatLookLikeThis?
  (clarified the last paragraph)
• [27.12] Are there any other sources of coding standards?
  (added a new URL thanks to Christopher Lott; added www.arcticlabs.com/codingstandards/ thanks to Richard)
• [28.4] Should I buy one book, or several?
  (rewrote; added the "programming by example" category)
• [31.2] What is "virtual data," and how-can / why-would I use it in C++?
  (fixed the sentence just before Pros & Cons list (changed StretchableArray to StretchableStack) thanks to Harri Klapuri)
• [32.2] How can I include a standard C header file in my C++ code?
  (added the whole section on "compiling C code with a C++ compiler," with inspiration thanks to Sebastian Kapfer)
• [33.6] How do I create and use an array of pointer-to-member-function?
  (removed the array size from the declaration of array a, that way there's one less thing to change if someone ever adds another function-pointer to the array thanks to Serge Ansay)
• [34.1] Why should I use container classes rather than simple arrays?
  (clarified "local" vs. "non-static local" thanks to Garen Parham)
• [37.1] Where can I download a free C++ compiler?
  (changed to a different site since the old URL was dead thanks to Victor R. Volkman)
• [37.5] Where can I get information about the C++ compiler from {Borland, IBM, Microsoft, Sun, etc.}?
  (fixed "Semantic" to "Symantec" and "Gary Comeau" to "Greg Comeau" thanks to Scott Tringali; fixed the URL to SGI's compiler thanks to Toon Knapen)
• [37.11] Is there a yacc-able C++ grammar?
  (rewrote; added a new grammar/lexer plus a new URL for the old grammar/lexer thanks to Ed Willink)
• [39.2] Is there a TeX or LaTeX macro that fixes the spacing on "C++"?
  (added a new LaTeX macro thanks to Bob Kline; rewrote)
• [39.3] Are there any pretty-printers that reformat C++ source code?
  (fixed