quadruple-precision

I use the <quadmath.h> . With which argument type can I read my input correctly? If I use double it looks like: printf("enter 3 values for s, t and mt:\n"); scanf("%lf %lf %lf", &s, &t, &mt); printf("%lf %lf %lf\n", s, t, mt); I tried different possibilities instead of "l" for example: scanf("%Qf %Qf %Qf", &s, &t, &mt); or even without scanf("%f %f %f", &s, &t, &mt); however I get an error. scanf (and related functions and printf and related functions) is not extensible . It can only parse what the standard library knows about. The C standard library comes with the operating system, not the

I try to execute the code #include <quadmath.h> #include <iostream> int main() { char* y = new char[1000]; quadmath_snprintf(y, 1000, "%Qf", 1.0q); std::cout << y << std::endl; return 0; } with commands g++ test.cpp -o test I get the error: /tmp/cctqto7E.o: In function `main': test.cpp:(.text+0x51): undefined reference to `quadmath_snprintf(char*, unsigned int, char const*, ...)' collect2: ld returned 1 exit status The version is: g++ --version g++ (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 Copyright (C) 2011 Free Software Foundation, Inc. This is free software; see the source for copying conditions

Just recently, the GCC 4.6.0 came out along with libquadmath . Unfortunately, GNU has supported Fortran, but not C or C++ (all that is included is a .so). I have not found a way to use these new features in C++, however, GNU C does support the __float128 type for guaranteed quadruple-precision floats. GNU C does not seem to support the math functions in libquadmath , such fabsq (absolute value, q being the suffix for quad). Is there any way to get these functions working in C++, or is there some alternative library that I could use for math functions with __float128 ? What is the best method