Find the first bit set in a bit string
#include <strings.h> int ffs( int value );
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The ffs() function finds the first bit set in value and returns the index of that bit. Bits are numbered starting from 1, starting at the rightmost bit.
The index of the first bit set, or 0 if value is zero.
POSIX 1003.1 XSI