Defining the default value for a ULONG& optional parameter as 0

Question

The following function declaration:

void Foo:DoSomething( ULONG &Count = 0) { .... }

Results in the following compile time error

error C2440: default argument cannot convert from 'int' to 'ULONG &'

What is the correct way of creating the signature so that when there is no parameter provided for Count its value will be zero.

@icepack sorry about that. Thanks – pondigi Feb 11 '13 at 21:03 — pondigi, Feb 11 '13 at 21:03

score 2 · Accepted Answer · answered Feb 11 '13 at 20:53

2

You're taking a non-const reference to Count, so it can't be assigned by default with r-value.

Use

void Foo:DoSomething( const ULONG &Count = 0) { .... }

void Foo:DoSomething( ULONG Count = 0) { .... }

answered Feb 11 '13 at 20:53

Stas

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score 1 · Answer 2 · answered Feb 11 '13 at 20:58

1

You can't do this for non-const references. A reference is pointing to an address in memory. Unless you specifically need reference semantics, I'd recommend just passing by value.

answered Feb 11 '13 at 20:58

Thomas Nelson

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Defining the default value for a ULONG& optional parameter as 0

2 Answers2