ffs(3C)
_________________________________________________________________
ffs function
Return the first bit in an integer that is one.
_________________________________________________________________
Calling Sequence
int ffs(), bitnum, number;
bitnum = ffs(number);
where number is the integer tested for the set bit.
Description
The ffs function returns the first bit set to 1 in an integer;
this function comes from the University of California Berkeley
UNIX (BSD) system.
Returns
The ffs function returns the first set bit, starting with the
least significant bit. For example, ffs(0) returns 0, ffs(1)
returns 1, and ffs(16) returns 5.
Related Functions
See also the bitset function.
Example
The following program demonstrates the ffs function for each
power of two from 0 - 15 and 0.
/* Program test for the ffs() function */
#include <stdio.h>
int ffs(), i = 1;
main() {
printf("ffs(%#08x) = %d.\n", i, ffs(i));
DG/UX 4.00 Page 1
Licensed material--property of copyright holder(s)
ffs(3C)
do {
i <<= 1;
printf("ffs(%#08x) = %d.\n", i, ffs(i));
} while (i != 0);
return 0;
}
DG/UX 4.00 Page 2
Licensed material--property of copyright holder(s)