These functions assign new values to already initialized integers (see Initializing Integers).
Set the value of rop from op.
mpz_set_f truncate op to
make it an integer.
Set the value of rop from str, a null-terminated C string in base base. White space is allowed in the string, and is simply ignored.
The base may vary from 2 to 62, or if base is 0, then the leading
characters are used:
0X for hexadecimal,
0B for binary,
0 for octal, or decimal otherwise.
For bases up to 36, case is ignored; upper-case and lower-case letters have the same value. For bases 37 to 62, upper-case letter represent the usual 10..35 while lower-case letter represent 36..61.
This function returns 0 if the entire string is a valid number in base base. Otherwise it returns -1.
Swap the values rop1 and rop2 efficiently.