On 2 April 2012 17:11, René Nyffenegger wrote: > I hope this is the right place to ask this question. It is. > I only > recently tried to compile gcc and it is obviously dependant > on mpfr, mpc and gmp. These seem to be high precision > mathematical libraries. Now, I am wondering why a compiler > not only needs one of these but even three of them. It needs three of them because they do different things. GCC requires MPFR in order to do floating point calculations are compile-time, so that e.g. pow(0.5, 4) can be replaced with a constant value instead of calling a function at run-time. GCC uses MFPR to get accurate, platform-independent results that don't depend on the host math library, which might be inaccurate or buggy. MPC is used to do similar optimisations for complex numbers. MPFR requires GMP. Before installing them please carefully read http://gcc.gnu.org/wiki/InstallingGCC As it says there, the simplest way to install them is from your OS package management system. The next best option is to use the contrib/download_prerequisites script in the GCC source. Either of those options should ensure everything just works. The last resort, which usually causes problems for people who don't know what they're doing, is to install the support library from source.
