not(3f) [bsd man page]

BIT(3F) 																   BIT(3F)

NAME

       bit - and, or, xor, not, rshift, lshift bitwise functions

SYNOPSIS

       (intrinsic) function and (word1, word2)

       (intrinsic) function or (word1, word2)

       (intrinsic) function xor (word1, word2)

       (intrinsic) function not (word)

       (intrinsic) function rshift (word, nbits)

       (intrinsic) function lshift (word, nbits)

DESCRIPTION

       These bitwise functions are built into the compiler and return the data type of their argument(s).  Their arguments must be integer or log-
       ical values.

       The bitwise combinatorial functions return the bitwise ``and'' (and), ``or'' (or), or ``exclusive or'' (xor) of two operands.  Not  returns
       the bitwise complement of its operand.

       Lshift,	or rshift with a negative nbits, is a logical left shift with no end around carry.  Rshift, or lshift with a negative nbits, is an
       arithmetic right shift with sign extension.  No test is made for a reasonable value of nbits.

       These functions may be used to create a variety of general routines, as in the following statement function definitions:

       integer bitset, bitclr, getbit, word, bitnum

       bitset( word, bitnum ) = or(word,lshift(1,bitnum))
       bitclr( word, bitnum ) = and(word,not(lshift(1,bitnum)))
       getbit( word, bitnum ) = and(rshift(word,bitnum),1)

FILES

       These functions are generated in-line by the f77 compiler.

4.2 Berkeley Distribution					  April 30, 1986							   BIT(3F)

BITSTRING(3)						   BSD Library Functions Manual 					      BITSTRING(3)

NAME

     bit_alloc, bit_clear, bit_decl, bit_ffs, bit_nclear, bit_nset, bit_set, bitstr_size, bit_test -- bit-string manipulation macros

SYNOPSIS

     #include <bitstring.h>

     bitstr_t *
     bit_alloc(int nbits);

     bit_decl(bitstr_t *name, int nbits);

     bit_clear(bitstr_t *name, int bit);

     bit_ffc(bitstr_t *name, int nbits, int *value);

     bit_ffs(bitstr_t *name, int nbits, int *value);

     bit_nclear(bitstr_t *name, int start, int stop);

     bit_nset(bitstr_t *name, int start, int stop);

     bit_set(bitstr_t *name, int bit);

     int
     bitstr_size(int nbits);

     int
     bit_test(bitstr_t *name, int bit);

DESCRIPTION

     These macros operate on strings of bits.

     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 refer-
     enced 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 ref-
     erenced by name.  If all bits are set, the location referenced by value is set to -1.

     The macros bit_clear(), bit_set() and bit_test() will evaluate the bit argument more than once, so avoid using pre- or post-, increment or
     decrement.  The arguments to the other macros are evaluated only once and may safely have side effects.

EXAMPLE

	   #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);
		   }
	   }

SEE ALSO

     malloc(3)

HISTORY

     The bitstring functions first appeared in 4.4BSD.

4th Berkeley Distribution					   July 19, 1993					 4th Berkeley Distribution