Am Mittwoch, 6. Januar 2016, 17:08:25 schrieb Yifang Tan: > Thanks! > I did upgrade gcc-4.9.0 by: > sudo apt-get install gcc-4.9 > It works now! Good to hear! > However, gcc is still the same version as gcc-4.8 as: > $ which gcc > /usr/bin/gcc -> gcc-4.8 > I am trying to understand why. Could you explain a little bit more why this > happened? You now have both gcc-4.8 and gcc-4.9 installed. The default compiler is still the old one, but the default libraries are the new ones, because they work with both compilers. You can use the new compiler by specifying gcc-4.9 directly on the command line. Best regards, -- Hannes Hauswedell PhD student Max Planck Institute for Molecular Genetics / Freie Universität Berlin address Institut für Informatik Takustraße 9 Room 019 14195 Berlin telephone +49 (0)30 838-75241 fax +49 (0)30 838-75218 e-mail hannes.hauswedell@[molgen.mpg.de|fu-berlin.de]