Problem Solved: #include <stdio.h> #include <math.h> int main(void) { _Decimal128 a = log(8.25123456); printf("%.62Lf\n",(long double)a); return 0; } Thanks for your replies. On Mon, Oct 04, 2010 at 03:03:27PM +0300, Bogdan Cristea wrote: > On Monday 04 October 2010 14:54:46 you wrote: > > I wish I could get 24 decimal digits precision with the current long > > double (80-bit). I can't get more than 15 digits even in a simple division. > > I think that the extended-precision can't give more than 19 decimal > > digits of precision (log(10,2^64)=19.2). The quadruple precision can > > give at most 34 decimal digits (log(10,2^113)=34). > > > > Please consider the example below: > > -------------------------------------------------- > > long double a = 1.0L/7.0L; > > printf("%Lf\n",a); > > -------------------------------------------------- > > > > Can't get more than 15 digits precision....-:( > > Is this a compiler problem or libc's problem? In x86_64 machines the > > long double values supposed to give at least 106-bit precision even when > > implemented in software. Is gcc compliant with the quadruple notation? > > Have you tried to specify manually the number of digits after the decimal > point ? > > long double a = 1.0L/7.0L; > printf("%'.100Lf\n",a); > > On a 64 bits machine the output is: > > 0.1428571428571428571409210675491330277964152628555893898010253906250000000000000000000000000000000000 > > regards > Bogdan -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html