I’m writing a command line program in ANSI C to parse a Quake 2 map file to report how many entities and textures are being used. My development machine is MacBook. I’m testing on OS X Snow Leopard (32-bit), Windows XP (32-bit) and Vista (64-bit), and Ubuntu 9.10 (32-bit).
The code is flawless on the OS X and GCC 4.2. The other platforms, not so flawless.
Visual Studio 2005 complained about an array declaration in the middle of the main() block — size info for the array isn’t available until then–that should be declared at top. Fixed that by declaring a pointer at top and writing a function to create the array.
Dev-C++ and GCC (3.4) on Windows has no complaints.
Cygwin and GCC (4.4) on Windows complained about array subscript has type char. I added (int) casts to fix that.
Ubuntu and GCC (4.4) is complaining about ignoring the return value of fread. Although I read elsewhere that I might be a bug in the way Ubuntu packaged GCC. Seems like this one in the context I’m using fread in may be safe to ignore. The warning only appears with the -O3 flag.
Except for Visual Studio 2005, all the compilers that I tested with are some version of GCC. Chasing down all these errors and warnings is serious pain in the butt. Until now, I been using the following flags in my Makefile:
debug: -pedantic -Wall
release: -O3
Is there a set of GCC flags that I should be using to catch all the errors on my primary development machine? Or is write once and test everywhere a fact of life?
Get yourself a copy of Lint. Lint is a static analysis tool that will pretty much cover the full range of compiler errors and warning and then some. As someone who frequently writes code targeting different platforms and compilers ensuring that the code passes through Lint is a pretty good barometer for getting the code to run across all compilers.
The best set of gcc flags to approximate lint is something like:
I also often use
if I am going to be writing 64-bit code because many compilers complain that long long is not a c++ type.
*Edit: Fixing copy and paste error in command line options