SafeBool< T > Class Template Reference

Safe conversion of objects in boolean context. More...

#include <SafeBool.h>

Inheritance diagram for SafeBool< T >:

Public Member Functions
	operator BoolType_t () const
	Bool operator implementation, derived class must provide a bool toBool() const function. More...

Protected Types
typedef void(base::*	BoolType_t) () const
	The bool type is a pointer to method that can be used in boolean context. More...

Protected Member Functions
void	invalidTag () const
	Nonimplemented call, use to disallow conversion between unrelated types. More...
void	trueTag () const
	Special member function that indicates a true value. More...

Detailed Description

template<typename T>
class SafeBool< T >

Safe conversion of objects in boolean context.

Classes wanting evaluation of their instances in boolean context must derive publicly from this class rather than implementing the easy to misuse operator bool().

Descendant classes must implement the function bool toBool() const to enable the safe conversion in boolean context.

Template Parameters

T	Type of the derived class

class A : public SafeBool<A> {
public:
 
     // boolean conversion
     bool toBool() const {
 
     }
};
 
class B : public SafeBool<B> {
public:
 
     // boolean conversion
     bool toBool() const {
 
     }
};
 
A a;
B b;
 
// will compile
if(a) {
 
}
 
// compilation error
if(a == b) {
 
}

Definition at line 113 of file common/SafeBool.h.

Member Typedef Documentation

BoolType_t

typedef void(base::* BoolType_t) () const

protectedinherited

The bool type is a pointer to method that can be used in boolean context.

Definition at line 50 of file common/SafeBool.h.

Member Function Documentation

operator BoolType_t()

operator BoolType_t

(

)

const

Bool operator implementation, derived class must provide a bool toBool() const function.

Definition at line 119 of file common/SafeBool.h.

invalidTag()

void invalidTag ( ) const

protectedinherited

Nonimplemented call, use to disallow conversion between unrelated types.

trueTag()

void trueTag ( ) const

protectedinherited

Special member function that indicates a true value.

Definition at line 60 of file common/SafeBool.h.