define a boolean type

[Krem]

Is that anyway we can create a boolean type with 1 bit size?
I came across a website advertising a C microcontroler compiler
with BIT and BYTE data types.

 bit     boolean;
 byte  message;

For byte data type, I think it using tydef of char as:
typedef unsigned char byte;
But I have no idea to create a bit date type.
Krem

[quzah]

#define bit unsigned char
#define byte unsigned char

Either way, you cannot have a variable that is only a single bit in size. You can get one bit variables only as members of a structure or union.

Quzah.

[Dave_Sinkula]

There are micros, such as the 8051, that have bit addressable memory. A compiler I have used for an 8051 derivative provides non-standard language extensions like a "bit" type to be used with this memory. Since it is non-standard, there is no general C solution for declaring an object that occupies a single bit.

[KingoftheWorld]

Originally posted by Krem
Is that anyway we can create a boolean type with 1 bit size?
I came across a website advertising a C microcontroler compiler
with BIT and BYTE data types.

 bit     boolean;
 byte  message;

For byte data type, I think it using tydef of char as:
typedef unsigned char byte;
But I have no idea to create a bit date type.
Krem

Sure, there is a way to create a user defined type
boolean with 1 bit size.

typedef struct { 
                unsigned char boolean : 1;
               } DataType;

KingoftheWorld
_________________________________________________
Love Relationship is like a Software Life Cycle development. It needs to be tried to understand carefully at the early phase and Keep up with enhancing and solid maitainence at the last phase!

[KingoftheWorld]

There is a error for my previous solution.
Here is the final code for bit data type.

typedef struct {
                 unsigned char TRUE  : 1;
                 unsigned char FALSE : 1; 
               } Boolean;

KingoftheWorld
_________________________________________________
Love Relationship is like a Software Life Cycle development. It needs to be tried to understand carefully at the early phase and Keep up with enhancing and solid maitainence at the last phase!

[Magos]

KingOfTheWorld: But that would still use 1 byte of memory.

[KingoftheWorld]

Originally posted by Magos
KingOfTheWorld: But that would still use 1 byte of memory.

You right, but boolean value consumes only
one bit of 1 byte char.
KingoftheWorld
_______________________________________________
Love Relationship is like a Software Life Cycle development. It needs to be tried to understand carefully at the early phase and Keep up with enhancing and solid maitainence at the last phase!