zypp::base::SafeBool< _Derived > Struct Template Reference

Validate objects in a boolean context without harmful side effects. More...

#include <SafeBool.h>

Inheritance diagram for zypp::base::SafeBool< _Derived >:

List of all members.

Public Types
typedef safebool_detail::SafeBoolBase::bool_type	bool_type
Public Member Functions
	operator bool_type () const
Protected Member Functions
	~SafeBool ()

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Detailed Description

template<class _Derived>
struct zypp::base::SafeBool< _Derived >

Validate objects in a boolean context without harmful side effects.

See also:

http://www.artima.com/cppsource/safebool.html

Uses CRTP to avoid a virtual function. _Derived must provide bool boolTest() const preformong the test.

Note:

Using SafeBool enables ==/!= comparision for Foo, based on the bool_type values. Make shure you overload both operators, in case an other semantic is desired for ==/!=.

 class Foo : protected base::SafeBool<Foo>
 {
 public:
   using base::SafeBool<Foo>::operator bool_type;

 private:
   friend SafeBool<TT>::operator bool_type() const;
   bool boolTest() const
   {
     // Perform Boolean logic here
   }
 };

Todo:

Investigate why Bit refuses private inheritance and exposition of operator bool_type. Seems to be a gcc bug. protected works.

Definition at line 70 of file SafeBool.h.

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Member Typedef Documentation

template<class _Derived>

typedef safebool_detail::SafeBoolBase::bool_type zypp::base::SafeBool< _Derived >::bool_type

Reimplemented from zypp::base::safebool_detail::SafeBoolBase.

Reimplemented in zypp::bit::BitField< _IntT >, zypp::bit::BitField< FieldType >, zypp::bit::BitField< uint64_t >, zypp::IdStringType< Derived >, zypp::IdStringType< ResKind >, zypp::IdStringType< Edition >, zypp::IdStringType< PoolQueryAttr >, zypp::IdStringType< PackageKeyword >, and zypp::IdStringType< SolvAttr >.

Definition at line 72 of file SafeBool.h.

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Constructor & Destructor Documentation

template<class _Derived>

zypp::base::SafeBool< _Derived >::~SafeBool

(

)

[inline, protected]

Definition at line 80 of file SafeBool.h.

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Member Function Documentation

template<class _Derived>

zypp::base::SafeBool< _Derived >::operator bool_type

(

)

const [inline]

Definition at line 73 of file SafeBool.h.

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The documentation for this struct was generated from the following file:

• zypp/base/SafeBool.h