BITMAP(3) | Library Functions Manual | BITMAP(3) |
__BITMAP_CLR
, __BITMAP_ISSET
,
__BITMAP_SET
, __BITMAP_SIZE
,
__BITMAP_TYPE
, __BITMAP_ZERO
—
#include <sys/bitops.h>
__BITMAP_CLR
(int
bit, type
*bitmap);
__BITMAP_ISSET
(int
bit, type
*bitmap);
__BITMAP_SET
(int
bit, type
*bitmap);
__BITMAP_SIZE
(type,
int nbits);
__BITMAP_TYPE
(name,
type,
int nbits);
__BITMAP_ZERO
(type
*bitmap);
FD_SET
() family, to the
setbit(9), macros and the
bitstring(3) library. They
are different from FD_SET
() because they are designed
to handle multiple sized bitmaps at the same time, and they can be of any
integral type. They are different from
setbit(9) because they can
operate on different integral types, not just on bytes. They are different
from bitstring(3) because
they are just macros, they don't allocate memory or use code, and they can be
used in both kernel and userland.
The following macros are provided for manipulating creating and manipulating bitmaps:
__BITMAP_CLR
(bit,
bitmap) removes the given bit
from the bitmap.
__BITMAP_ISSET
(bit,
bitmap) is non-zero if bit is a
member of bitmap, zero otherwise.
__BITMAP_SET
(bit,
bitmap) Sets the given bit in
the bitmap.
__BITMAP_SIZE
(type,
nbits) Returns the number of elements would be
required of the given type to hold
nbits.
__BITMAP_TYPE
(name,
type, nbits) Declares the
properly sized bitmap structure of the given type that
holds nbits and is named
name.
__BITMAP_ZERO
(bitmap)
initializes a descriptor set pointed to by bitmap to
the null set.
The behavior of these macros is undefined for negative bit values or ones greater than the number of bits the bitmap can hold.
#include <sys/bitops.h> int main(int argc, char **argv) { __BITMAP_TYPE(, uint32_t, 5000) bitmap; /* Initialize the read set to null */ __BITMAP_ZERO(&bitmap); /* Set bit 1 */ __BITMAP_SET(1, &bitmap); for (size_t i = 0; i < 5000; i++) { if (__BITMAP_ISSET(i, &bitmap)) { /* Should just print 1 */ printf("Bit %zu is set\n", i); __BITMAP_CLR(i, &bitmap); } break; } return 0; }
__BITMAP_*
() macros appeared in
NetBSD 7.0.
March 8, 2018 | NetBSD 9.0 |