bitvalue(3C)
_________________________________________________________________
bitvalue $builtin function
Return the current value of a bit.
_________________________________________________________________
Calling Sequence
#include <bit.h>
int bitvalue();
short *ptr;
int offset, value;
value = bitvalue(ptr, offset);
or
$builtin int bitvalue();
short *ptr;
int offset, value;
value = bitvalue(ptr, offset);
Description
The bitvalue function returns the value of the bit specified by a
word pointer, ptr, and a non-negative bit offset, offset. Note
that the most significant bit in the 16-bit word pointed to by
ptr is at offset 0, and the least significant bit is at offset
15. If the offset is negative, the bitvalue routine may cause an
error.
The first calling sequence noted above uses a function call. The
second might generate smaller or faster code, but may not run
under other C compilers.
The include file bit.h defines this function.
Returns
The bitvalue function returns 0 or 1 depending on whether the bit
addressed is 0 or 1.
Related Functions
See also the bitset and bitszbo functions.
Example
DG/UX 4.00 Page 1
Licensed material--property of copyright holder(s)
bitvalue(3C)
/* Program test for the bitvalue() function */
#include <bit.h>
#include <stdio.h>
short s, bit15, bit0;
main() {
s = 3; /* bits 15 & 14 are 1 */
bit0 = bitvalue(&s, 0); /* value on bit 0 */
bit15 = bitvalue(&s, 15); /* value on bit 15 */
(void) printf("s = %hx (hexadecimal)\n", s);
(void) printf("bit0 = %d\n", bit0);
(void) printf("bit15 = %d\n", bit15);
}
The above program produces the output
s = 3 (hexadecimal)
bit0 = 0;
bit15 = 1;
DG/UX 4.00 Page 2
Licensed material--property of copyright holder(s)