ANSI "C" supports bitfields, which are a special type of structure field.

In ANSI "C" multiple bitfields are crunched together into one "int" sized
value (note: NOT a char!).

The syntax is like this:

typedef struct  {
    int        field_1 : 1;        // single bit field
    int        field_2 : 1;
    int        field_3 : 5;        // 5-bit field
} bitfield_struct;

you can do this too:

typedef union {
    int                    as_integer;
    bitfield_struct    as_fields;
} bitfield_union;

bitfield_union myvar;

myvar.as_fields.field_3 = 2;
myvar.as_fields.field_1 = 0;

save_it( myvar.as_integer );

Bob Ammerman
RAm Systems

----- Original Message -----
From: "Sean H. Breheny" <shb7@CORNELL.EDU>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, December 03, 2001 12:27 PM
Subject: Re: [pic]:Accessing a var as a byte or bits in C


> Hi Andrew,
>
> Is this specific to HiTech? I have never seen a "normal" C compiler which
> had a bit variable type, and I thought that either the ANSI or K&R
> standards did not call for such a type.
>
> Sean
>
> At 11:31 AM 12/3/01 -0700, you wrote:
> >Re:
> >
> >>In Hitech C, is it possible to access the same variable as two
> >>different types in C, specifically bits and bytes ?
> >>For example I want some bit variables for various option flags, but
> >>want to access them all as a single byte when saving/loading them to
> >>eeprom.
> >>
> >>Can unions be used to do this ?
> >
> >
> >Yes.
> >--
> >
> >  ______________________________________
> >   Andrew E. Kalman, Ph.D.   aek@pumpkininc.com
> >
> >--
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