CODEWITHSUNDEEP
c++boolean
user258872
user258872

Reputation: 43

difference and advantages between BOOL and bool

I've been playing with some functions that return BOOL. I know how to use them but whats the difference between BOOL and bool? I've also looked at some example code from directX and they use it as a int? Is there a advantage to using int, bool, or BOOL? My main question is Which should I be using?

Upvotes: 2

Views: 960

Answers (4)

glampert
glampert

Reputation: 4421

Most compilers will make the size of a bool 1 byte, whereas the size of an int is usually 4 bytes. There is an obvious saving in space if you use bool for tightly packed structures in this case.

Now, in theory, moving and int around is faster than moving a byte (int is usually the native machine word). So in the sense of microoptimizations for maximum speed, a BOOL that equals an int is better than a bool that equal a byte.

Upvotes: 0

user3527357
user3527357

Reputation:

Is there a advantage to using int, bool, or BOOL?

One advantage of using bool over BOOL is that you can overload functions on bool.

// header file
void f( int  ); // ok
void f( BOOL); // ok, redeclares the same function

...

// source file
void f( int  ) { /*...*/ }   // ok
void f( BOOL) { /*...*/ }   // error, redefinition

For more information about why it makes sense to use bool over BOOL read this gotw by Herb Sutter

Upvotes: 1

sj0h
sj0h

Reputation: 912

For the best type safety, in new code you should use bool for a boolean. If you interface with things like a BOOL, automatic type conversion will generally work for you, but otherwise you just treat BOOL as a legacy integer represented boolean.

Upvotes: 1

Keith Thompson
Keith Thompson

Reputation: 263667

BOOL is a Windows-specific type name; it's a typedef (an alias) for int.

Historically, it was probably invented by Microsoft before the built-in bool type was added to C++.

For any new code that doesn't have to talk to the Windows API, just use bool.

Use BOOL only for code that has to conform to the Windows API.

(If the Windows API were being written from scratch today, presumably it would use C++'s built-in bool type rather than inventing its own. BOOL is a relic of history.)

Upvotes: 5

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