ccwarn

ccwarn, aka C and C++ Warnings, tests C or C++ source against both GCC and Clang automatically.

Why ccwarn?

Both GCC and Clang are popular C and C++ compilers among Unix or Unix-like systems. They can optionally emit non-erroneous warning messages during compilations. Programmers should try their best to reduce those warnings for better code quality.

Nevertheless, it is tedious to write Makefile or another project configuration file for each code base. To address this issue, ccwarn automatically tests your code base against both Clang and GCC without any project configuration file.

In addition to code warnings, ccwarn can be used to test language standard conformity for your code base against both GCC and Clang as well.

ccwarn intends to test small code base because ccwarn doesn't rely on any external project configuration, unsuitable for large and complex projects.

System Requirements

ccwarn itself is written in POSIX shell. Besides a shell, ccwarn depends on both GCC and Clang.

ccwarn will check these dependencies, emitting an error message if neither is installed on your system.

We tested ccwarn against several Unix variants:

• macOS Big Sur
• Ubuntu 20.04 LTS
• Rocky Linux 8.5
• openSUSE Leap 15.3
• FreeBSD 13.0

It should work on other Unix systems as well.

Supported File Formats

ccwarn supports the following file formats:

• .c for C source
• .cpp, .cxx or .cc for C++ source

ccwarn can handle projects that mix C and C++ together.

Supported Language Standards

C Standards

• C89: c89, c90, ansi
• C99: c99, c9x
• C11: c11, c1x
• C17: c17, c18
• C20: c2x

C++ Standards

• C++98: c++98, c++03
• C++11: c++11, c++0x
• C++14: c++14, c++1y
• C++17: c++17, c++1z
• C++20: c++2a

Usage

Before using ccwarn, add executable mode to it:

$ chmod +x path/to/ccwarn

Then, copy ccwarn to a valid $PATH like $HOME/bin or /usr/local/bin to use it.

Test single C file:

$ ccwarn path/to/file.c

Test multiple files in a project:

$ ccwarn path/to/*.c

Test for C and C++ mixed code base:

$ ccwarn path/to/*.c path/to/*.cpp

Show help info:

$ ccwarn help

Environment Variables

You can adjust the behavior of ccwarn with the following environment variables:

• GCC to set GCC compiler
• GXX to set G++ compiler
• CLANG to set Clang compiler
• CLANGXX to set Clang++ compiler
• CSTD to set C standard, default to C11
• CXXSTD to set C++ standard, default to C++17
• CFLAGS to set custom include paths and compiler flags for C
• CXXFLAGS to set custom include paths and compiler flags for C++

All environment variables are optional, set with sensible default values.

Breaking Changes

ccwarn checks target source by compiling and executing it. Hence, DON'T USE ccwarn to test UNTRUSTED source. Instead of running input source, ccwarn only compiles source into objects with warnings enabled now. Therefore, main function is not required to run ccwarn.

Note

If you just want to run some C or C++ source, see ccrun.

License

Copyright (c) 2019-2022 Michelle Chen; licensed under MIT.