Recommended GCC warning options for C

I started out with C++, so when I made the switch to learning C I made sure to be extra-anal:

• -fmessage-length=0
• -ansi -pedantic -std=c99
• -Werror
• -Wall
• -Wextra
• -Wwrite-strings
• -Winit-self
• -Wcast-align
• -Wcast-qual
• -Wpointer-arith
• -Wstrict-aliasing
• -Wformat=2
• answered 2009-01-06T02:05:46.020

-Wall -W -Wextra -Wconversion -Wshadow -Wcast-qual -Wwrite-strings -Werror

I took that list mostly from the book "An Introduction to GCC" (by rms) and then some from Ulrich Drepper's recommendation about defensive programming (slides for Defensive Programming).

But I don't have any science behind my list. It just felt like a good list.

Note: I don't like those pedantic flags though...

Note: I think that -W and -Wextra are more or less the same thing.

-Wfloat-equal, -Wshadow, and -Wmissing-prototypes.

The warning about uninitialized variables doesn't work unless you specify -O, so I include that in my list:

-g -O -Wall -Werror -Wextra -pedantic -std=c99

Documentation on each warning:

• -g
• -O
• -Wall
• -Werror
• -Wextra
• -pedantic
• -std=c99