Migrating to gcc-4.1

gcc-2.95 was a high point for gcc. In fact, it was better in many respects than gcc-3.0 and gcc-3.2; many projects (e.g. the Linux Kernel) continued to use gcc-2.95.x for years due to code quality and stability issues with newer versions of gcc. But gcc-4.1 is quite good, and has improvements like much better C++ support, support for modern 64 bit processors, and profile-driven optimization. It is finally time for even the most conservative of projects to update from gcc-2.95.x to a current version of gcc.

Like Rip Van Winkle, those programmers who have been slumbering in gcc-2.95-land for the last five years will awake to a changed landscape when they start using gcc-4.1.x. Below is a list of resources for people porting code from gcc-2.95.x to gcc-4.1.x.

Migration / Portability Guides

The very first thing one should read is "C++ specific improvements" in the gcc-3.4 release notes! This describes the ways in which the C++ parser in gcc-3.4.0 and later is stricter than the parser in older versions of gcc.
Ben Hutching's "Common Syntax Errors in C++"
Building the whole Debian archive with GCC 4.1: a summary
PortingToGCC (4.0) - from Apple. Describes Apple's early snapshot of gcc-4.0.
Migration Guide for gcc 3.2 by Charles Leggett
From gcc-2.95 to gcc-3.2 by Sebastien Ponce (text version)
GCC: Migrating to version 3.2 from the BYU CS department
Getting the Best from G++ by Nathan Sidwell
Mozilla C++ portability guide (partly Mozilla-specific, but some good stuff)
Pre-defined C/C++ Compiler Macros - lots of good information about platform-specific predefined macros

If you know of any other good migration guides, please email a link to dank at kegel.com so I can update the list.

GNU Compiler Change Notes

"GCC 4.1 Release Series: Changes, New Features, and Fixes" - the official Gnu release notes for gcc-4.1

"GCC 4.0 Release Series: Changes, New Features, and Fixes" - the official Gnu release notes for gcc-4.0

"GCC 3.4 Release Series: Changes, New Features, and Fixes" - the official Gnu release notes for gcc-3.4

"GCC 3.3 Release Series: Changes, New Features, and Fixes" - the official Gnu release notes for gcc-3.3

"GCC 3.2 Release Series: Changes, New Features, and Fixes" - the official Gnu release notes for gcc-3.2

"GCC 3.0 Release Series: New Features" - the official Gnu release notes for gcc-3.0

C++ FAQs

Getting Better Error Messages

Sometimes gcc doesn't produce the greatest error messages. One way to decode cryptic messages is to extract the code snippet in question, and compile it with a different compiler, e.g. Comeau C++, which has a free online compiler which is quite handy for just that purpose, and often has better error messages.

Last update: 10 May 2006