NAME
setbit —
macros related to bitmaps
SYNOPSIS
#include
<sys/param.h>
void
setbit(array,
x);
void
clrbit(array,
x);
int
isset(array,
x);
int
isclr(array,
x);
DESCRIPTION
Thesetbit family of macros operate with bitmaps, also
known as bit arrays.
In a nutshell,
setbit()
sets the bit x in array,
clrbit()
clears it,
isset()
tests whether x is set, and
isclr()
returns 1 if x is not set.
EXAMPLES
The following example declares a buffer of 10 chars, treating it as an array of 80 bits:
char buf[10]; ... setbit(buf, 12); /* set the fifth bit in the second byte */
SEE ALSO
CAVEATS
The number of valid bits in a given array is assumed to be
multiple of CHAR_BIT, the number of bits for
smallest object that is not a bit-field.