/* in this example, I think there was a pb in the old function :
result of mpfr_set_str_old for the same number, but with more
result of mpfr_set_str_old for the same number, but with more
precision is: 1.111111111110000000000000000111111111111111111111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100111000100001100000010101100111010e184