Overlook

Overlook: a cmake plugin for safer c/c++ programming.

Introduction

overlook.cmake collects 30+ warnings, mark them as errors, help you found bugs when compile C/C++ code.

Usage

Download overlook.cmake and included it in CMakeLists.txt:

include("overlook.cmake")  # Done. So easy!

Alternatively, if you don't want globally enable overlook, you may apply it for specific target:

set(OVERLOOK_APPLY_FLAGS_GLOBAL OFF)
include("overlook.cmake")
target_compile_options(your_target_name
  PRIVATE # or PUBLIC
  ${OVERLOOK_CXX_FLAGS} # C++
  # ${OVERLOOK_C_FLAGS} # C
)

Then compile your projec as usual, it will report bugs more seriously thanks to overlook.

Purpose

Good programmers should not ignore warnings. Treating all warnings as errors, however, is not practical due to reasons:

• time cost
• not own scratch project, too much to modify
• not affect result

Moreover, on the GCC/Clang common flags:

• -Wall does not mean turn on all warnings, missing flags like -Wnon-virtual-dtor
• -Wpedantic check more flags that -Wall, but still missing flags like -Wnon-virtual-dtor
• -Weffc++ may cover more flags

Here comes the contradiction: which warnings should be considered carefully?

In overlook.cmake, there are 36 serious compilation warnings' checking, treat corresponding C/C++ flags as error, with corresponding unit tests (See tests). Most are extracted from practical cross-platform projects, and does resolve severe bugs such as:

• Segmentation Faults(caused by address truncation)
• Memory leaks(caused by missing including header file)
• Trap(caused by missing return value)

These severe bugs can not be inspected by famous tools like AddressSanitizer, Valgrind, VLD, but overlook.cmake can. People may also use clang-tidy, which will report more compile warnings (instead of compile errors).

♥️ Thanks

If you like this project, welcome Star!

Advanced Usage

Disable a specific warning

Compile your code with overlook.cmake applyed, see that error nessage's type/number, search it in overlook.cmake and comment it out via inserting #, such as:

#if(OVERLOOK_ENABLE_RULE32)
#  if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
#    if(CMAKE_CXX_COMPILER_VERSION GREATER 7.5)
#      overlook_list_append(OVERLOOK_CXX_FLAGS -Werror=class-memaccess)
#    endif()
#  endif()
#endif()

Options

You may override the following options:

option(OVERLOOK_APPLY_FLAGS_GLOBAL "Apply overlook globally?" ON)

Debugging

If you're using Overlook, but it seems not work, possible cases:

1. The overlook.cmake you are using is not the latest.
2. Overlook's rules are suppressed due to your add_definitions(-w), which ignore all warnings thus overlook won't work.
3. Your compiler is not covered by Overlook. If so, text me or create an issue.

What about Makefile?

See makefiles.

References

• https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines
• https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html