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.