Sets bit index in num.
The value to modify.
A GMP object, an int or a numeric string.
The index of the bit to set. Index 0 represents the least significant bit.
True to set the bit (set it to 1/on); false to clear the bit (set it to 0/off).
A GMP object.
Unlike most of the other GMP functions, gmp_setbit must be called with a GMP object that already exists (using gmp_init for example). One will not be automatically created.