unary_function<Arg, Result>
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| Category: functors |
Component type: type |
Description
Unary_function is an empty base class: it contains no member
functions or member variables, but only type information. The
only reason it exists is to make it more convenient to define
types that are models of the concept Adaptable Unary Function.
Specifically, any model of Adaptable Unary Function must define
nested typedefs. Those typedefs are provided by the base
class unary_function.
Example
struct sine : public unary_function<double, double> {
double operator()(double x) { return sin(x); }
};
Definition
Defined in the standard header functional, and in the nonstandard
backward-compatibility header function.h.
Template parameters
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Parameter
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Description
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Default
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Arg
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The function object's argument type
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Result
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The function object's result type
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Model of
Assignable, Default Constructible
Type requirements
Public base classes
None.
Members
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Member
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Where defined
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Description
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argument_type
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unary_function
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See below.
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result_type
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unary_function
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See below.
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New members
These members are not defined in the
Assignable and Default Constructible
requirements, but are specific to
unary_function.
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Member
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Description
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argument_type
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The function object's argument type. This is a typedef for the
template parameter Arg.
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result_type
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The function object's result type. This is a typedef for the
template parameter Result.
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Notes
See also
The Function Object overview, Adaptable Unary Function,
binary_function
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