a non-NULL field / pointer to an array of unsigned integers.
a bit number, starting with bit 0 of p[0], and progressing. It addresses bits like the expression:
p[index / (T.sizeof*8)] & (1 << (index & ((T.sizeof*8) - 1)))
A non-zero value if the bit was set, and a zero if it was clear.
size_t[2] array; array[0] = 2; array[1] = 0x100; assert(btc(array.ptr, 35) == 0); if (size_t.sizeof == 8) { assert(array[0] == 0x8_0000_0002); assert(array[1] == 0x100); } else { assert(array[0] == 2); assert(array[1] == 0x108); } assert(btc(array.ptr, 35)); assert(array[0] == 2); assert(array[1] == 0x100); assert(bts(array.ptr, 35) == 0); if (size_t.sizeof == 8) { assert(array[0] == 0x8_0000_0002); assert(array[1] == 0x100); } else { assert(array[0] == 2); assert(array[1] == 0x108); } assert(btr(array.ptr, 35)); assert(array[0] == 2); assert(array[1] == 0x100);
Tests and sets the bit.