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

The setbit 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

bitmap(3), bitstring(3)

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.