| BITSTRING(3) | Library Functions Manual | BITSTRING(3) | 
bit_alloc, bit_clear,
  bit_decl, bit_ffc,
  bit_ffs, bit_nclear,
  bit_nset, bit_set,
  bitstr_size, bit_test —
#include <sys/types.h>
#include <bitstring.h>
bitstr_t *
  
  bit_decl(bitstr_t
    *name, size_t
    nbits);
bitstr_t *
  
  bit_alloc(size_t
    nbits);
bit_clear(bitstr_t
    *name, size_t
  bit);
bit_ffc(const
    bitstr_t *name, size_t
    nbits, int
  *value);
bit_ffs(const
    bitstr_t *name, size_t
    nbits, int
  *value);
bit_nclear(bitstr_t
    *name, size_t
    start, size_t
    stop);
bit_nset(bitstr_t
    *name, size_t
    start, size_t
    stop);
bit_set(bitstr_t
    *name, size_t
  bit);
bitstr_size(size_t
    nbits);
bit_test(const
    bitstr_t *name, size_t
    bit);
The macro bit_alloc() returns a pointer of
    type “bitstr_t” to sufficient space to
    store nbits bits, or NULL if
    no space is available.
The macro bit_decl() allocates sufficient
    space to store nbits bits on the stack.
The macro bitstr_size() returns the number
    of elements of type bitstr_t necessary to store
    nbits bits. This is useful for copying bit
  strings.
The macros bit_clear() and
    bit_set() clear or set the zero-based numbered bit
    bit, in the bit string name.
The bit_nset() and
    bit_nclear() macros set or clear the zero-based
    numbered bits from start to stop
    in the bit string name.
The bit_test() macro evaluates to non-zero
    if the zero-based numbered bit bit of bit string
    name is set, and zero otherwise.
The bit_ffs() macro stores in the location
    referenced by value the zero-based number of the first
    bit set in the array of nbits bits referenced by
    name. If no bits are set, the location referenced by
    value is set to -1.
The macro bit_ffc() stores in the location
    referenced by value the zero-based number of the first
    bit not set in the array of nbits bits referenced by
    name. If all bits are set, the location referenced by
    value is set to -1.
The arguments to these macros are evaluated only once and may safely have side effects.
#include <limits.h>
#include <bitstring.h>
...
#define	LPR_BUSY_BIT		0
#define	LPR_FORMAT_BIT		1
#define	LPR_DOWNLOAD_BIT	2
...
#define	LPR_AVAILABLE_BIT	9
#define	LPR_MAX_BITS		10
void
make_lpr_available(void)
{
	bitstr_t bit_decl(bitlist, LPR_MAX_BITS);
	...
	bit_nclear(bitlist, 0, LPR_MAX_BITS - 1);
	...
	if (!bit_test(bitlist, LPR_BUSY_BIT)) {
		bit_clear(bitlist, LPR_FORMAT_BIT);
		bit_clear(bitlist, LPR_DOWNLOAD_BIT);
		bit_set(bitlist, LPR_AVAILABLE_BIT);
	}
}
bitstring functions first appeared in
  4.4BSD.
| December 29, 2016 | NetBSD 9.4 |