The macro Fn bit_alloc returns a pointer of type ``Fa bitstr_t * '' to sufficient space to store Fa nbits bits, or NULL if no space is available.
The macro Fn bit_decl allocates sufficient space to store Fa nbits bits on the stack.
The macro Fn bitstr_size returns the number of elements of type Fa bitstr_t necessary to store Fa nbits bits. This is useful for copying bit strings.
The macros Fn bit_clear and Fn bit_set clear or set the zero-based numbered bit Fa bit , in the bit string name
The Fn bit_nset and Fn bit_nclear macros set or clear the zero-based numbered bits from Fa start to Fa stop in the bit string name
The Fn bit_test macro evaluates to non-zero if the zero-based numbered bit Fa bit of bit string Fa name is set, and zero otherwise.
The Fn bit_ffs macro stores in the location referenced by Fa value the zero-based number of the first bit set in the array of Fa nbits bits referenced by Fa name . If no bits are set, the location referenced by Fa value is set to -1.
The macro Fn bit_ffc stores in the location referenced by Fa value the zero-based number of the first bit not set in the array of Fa nbits bits referenced by Fa name . If all bits are set, the location referenced by Fa 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
make_lpr_available()
{
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);
}
}