Fills bit-string with zeroes if initialization is
#f; otherwise fills bit-string with ones. Returns an unspecified value.
Moves the contents of bit-string into target-bit-string. Both arguments must be bit strings of the same length. The results of the operation are undefined if the arguments are the same bit string.
Destructively copies the bits of bit-string-1, starting at index start1 (inclusive) and ending at end1 (exclusive), into bit-string-2 starting at index start2 (inclusive). Start1 and end1 must be valid substring indices for bit-string-1, and start2 must be a valid index for bit-string-2. The length of the source substring must not exceed the length of bit-string-2 minus the index start2.
The bits are copied starting from the MSB and working towards the LSB; the direction of copying only matters when bit-string-1 and bit-string-2 are