Gcc4 (now in updates) Questions

[Matthew Saltzman]

On Tue, 12 Apr 2005, Matthew Miller wrote:

> On Tue, Apr 12, 2005 at 05:52:22PM -0400, David Cary Hart wrote:
>> Now that gcc4 is in updates (and I am a C nitwit):
>>         GCC 3.4 was updated but remains on the system, correct?
>
> Right; that was an update from 3.4.2 to 3.4.3.
>
>>         Do I now have to make a GCC choice when building a package or
>>         compiling an RPM?
>
> Yes; gcc4 is installed as, surprisingly enough, gcc4, so you can just use
> that instead of gcc.
>
>>         Can I assume that some things will compile with gcc4 and some
>>         won't?
>
> Probably.
>
>>         If that's correct, can I further assume that, what will compile
>>         with gcc4, should be compiled with gcc4?
>
> Depends on how brave you are and or how reliable you need to be. Code might
> compile apparently fine but be created slightly wrong, or the new compiler
> may expose bugs in the code you're building that just happened to work
> before. (This happened a lot with going from gcc 2.x to 3.)

You probably don't want to compile code from other sources with gcc4 
unless told to explicitly.  Much published code is probably not gcc4 
ready, and code that needs to integrate with stuff already on your system 
may break something.

Feel free to experiment with gcc4 on your own application code, though.

-- 
 		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs