Saturday, January 22, 2011

How to use older version of gcc

Hi all,

This post is for my friends who want to use an older version of gcc/g++ compiler but don't know how (Assuming they are on latest Ubuntu where in the default g++ package installs 4.4 or above). In synaptic versions of gcc ranging from 4.1 are available (at-least they do on Ubuntu 9.10).
When i first googled/binged the question, it was difficult for me to get an answer. No were its mentioned on how to use older version. But just by luck i tired "g++-4.1" and it worked like charm :)

For using an older version (Off-course after installation) supply the version number along with g++ command, eg for version 4.3 use "g++-4.3" no space in between. It will compile the code.

Why we need older versions ??

Its mainly because sites like etc support gcc 4.3 but not above (The last time i saw), there is considerable difference between various versions of gcc () , which most of the time must not matter to a user. But sometimes when compiling a old code (I was stuck with COOL language in my compilers assignment), one need an older version.

The changes incorporated in various versions are available at in the form of change logs.

By default g++ will map to the highest version of g++ installed (by selecting g++ or g++ multilib in synaptic). I think there must be a way to change this mapping . Any one know about it ??

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