casa::DefaultValue_global_functions_defval Struct Reference
[Utilities]

#include <DefaultValue.h>

List of all members.

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Detailed Description

A templated function which sets a variable to a default value.

Intended use:

Part of API

Review Status

Reviewed By:

syang@nrao.edu<dt>Date Reviewed:1996/03/14

Test programs:

tDefaultValue

Prerequisite

• none

Etymology

The DefaultValue function name is derived from its use to fill a data type with a default value, usually zero.

Synopsis

The DefaultValue function is passed an instance of a data type and the variable is filled with a default value. The majority of classes may use the templated version here. Special classes may use their own non-templated specializations as demonstrated in .\./Utilities/test/tDefaultValue.cc.

Example

    Int foo = 35;
    defaultValue(foo);
    AlwaysAssert(foo == 0, AipsError);
    Array<Float> bar;
    defaultValue(bar);
    AlwaysAssert(allEQ(bar, 0.0f), AipsError);

A special class may need its own implementation:

    void defaultValue(MySpecialClass &val){
     // make a default value be all zeros
     val.operator()(IPosition(2,3,4)) = Table.keywords().defaultval();
    };

Motivation

We needed a common way of setting all objects to zero or some null/default value. Specializing a templated function seemed the only way to reach everyone.

Template Type Argument Requirements (T)

• constructor T(Int)
• assignment operator (copy semantics)

Thrown Exceptions

• none

To Do

• none

Definition at line 100 of file DefaultValue.h.

Public Member Functions
template<class T>
void	defaultValue (T &theValue)

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Member Function Documentation

template<class T>

void casa::DefaultValue_global_functions_defval::defaultValue

(

T &

theValue

)

[inline]

Definition at line 101 of file DefaultValue.h.

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

• casa/implement/Utilities/DefaultValue.h

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