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Gabriel Dos Reis
GitHub
commit
5827b64a5f
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@ -7255,7 +7255,7 @@ Union rule summary:
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* [C.180: Use `union`s to save Memory](#Ru-union)
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* [C.181: Avoid "naked" `union`s](#Ru-naked)
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* [C.182: Use anonymous `union`s to implement tagged unions](#Ru-anonymous)
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* [C183: Don't use a `union` for type punning](#Ru-pun)
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* [C.183: Don't use a `union` for type punning](#Ru-pun)
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* ???
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### <a name="Ru-union"></a>C.180: Use `union`s to save memory
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@ -7338,8 +7338,8 @@ The soon-to-be-standard `variant` type (to be found in `<variant>`) does that fo
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##### Reason
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A well-designed tagged usin is type safe.
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An *anonymous* union simplifies the definition of a class with a (tag,union) pair.
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A well-designed tagged union is type safe.
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An *anonymous* union simplifies the definition of a class with a (tag, union) pair.
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##### Example
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@ -7348,7 +7348,7 @@ You can look there for an explanation.
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The code is somewhat elaborate.
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Handling a type with user-defined assignment and destructor is tricky.
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Saving programmers from haing to write such code is one reason for including `variant` in the standard.
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Saving programmers from having to write such code is one reason for including `variant` in the standard.
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class Value { // two alternative representations represented as a union
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private:
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@ -7450,7 +7450,7 @@ Type punning using a `union` is a source of errors.
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unsigned char c[sizeof(int)];
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};
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The idea of `Pun` is to be able to look at the characte representation of an `int`.
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The idea of `Pun` is to be able to look at the character representation of an `int`.
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void bad(Pun& u)
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{
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@ -9081,7 +9081,7 @@ Can cause maintenance problems.
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If this is a large `if`-statement, it is easy to overlook that a new `d` has been introduced in the inner scope.
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This is a known source of bugs.
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Sometimes suce reuse of a name in an inner scope is called "shadowing".
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Sometimes such reuse of a name in an inner scope is called "shadowing".
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##### Note
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@ -10780,11 +10780,11 @@ Avoid wrong results.
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##### Example
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int x = -3;
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unsigned int y = 7;
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cout << x-y << '\n'; // unsigned result, possibly 4294967286
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cout << x+y << '\n'; // unsiged result: 4
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cout << x*y << '\n'; // unsigned result, possibly 4294967275
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unsigned int y = 7;
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cout << x - y << '\n'; // unsigned result, possibly 4294967286
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cout << x + y << '\n'; // unsigned result: 4
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cout << x * y << '\n'; // unsigned result, possibly 4294967275
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It is harder to spot the problem in more realistic examples.
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@ -10825,7 +10825,7 @@ can be surprising for many programmers.
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##### Reason
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Because most arithmetic is assumed to be signed;
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`x-y` yields a negative number when `y>x` except in the rare cases wrhere you really want modulo arithmetic.
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`x-y` yields a negative number when `y>x` except in the rare cases where you really want modulo arithmetic.
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##### Example
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@ -16463,7 +16463,7 @@ and errors (when we didn't deal correctly with semi-constructed objects consiste
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* Always establish a class invariant in a constructor.
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* Don't define an object before it is needed.
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### <a name="Rnr-goto-exit"></a>NR.6: Don't: Place all cleanup actions at the end of a fucntion and `goto exit`
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### <a name="Rnr-goto-exit"></a>NR.6: Don't: Place all cleanup actions at the end of a function and `goto exit`
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##### Reason (not to follow this rule)
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@ -16505,7 +16505,7 @@ and spot the bug.
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##### Alternative
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* [M]ake member data `public` or (preferably) `private`](#Rh-protected)
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* [Make member data `public` or (preferably) `private`](#Rh-protected)
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# <a name="S-references"></a>RF: References
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@ -1,5 +1,6 @@
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'
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0xFF0000
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0b0101'0101
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'14
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2D
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2K
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@ -47,6 +48,7 @@ BDE
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behaviorless
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BigPOD
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Bjarne
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blog
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Bloomberg
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Boehm
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bool
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@ -181,6 +183,7 @@ gp
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GPLv3
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gsl
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GSL
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GSL's
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gx
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handcoded
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Henricson
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@ -261,6 +264,7 @@ memoized
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memset
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metameta
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metaprogram
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metaprograms
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metaprogramming
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Metaprogramming
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Meyers01
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@ -272,6 +276,7 @@ microbenchmarks
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modify1
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modify2
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moredata
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multithreaded
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msgsl
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mtx
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Murray93
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@ -342,6 +347,7 @@ polymorphically
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POPL
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PortHandle
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PostInitialize
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pp216
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PPP
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pre
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Pre
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