CheckWarning.cmake

Check for compiler warnings in CMake projects.

This module enables compiler warnings to be checked easily in CMake projects. By default, it enables all recommended warning flags on targets across different compilers, preventing users from having to manually specify warning flags to be enabled.

This module provides two utility functions for checking compiler warnings:

• target_check_warning: For checking compiler warnings on a single target.
• add_check_warning: For checking compiler warnings on all targets in the current directory.

These functions enable all recommended warning flags on the targets and can optionally be set to treat the warnings as errors.

Key Features

• Supports checking warnings on MSVC, GNU, and Clang compilers.
• Optionally treats warnings as errors.
• Simple syntax and easy integration.

Usage Guide

Module Integration

The recommended way to integrate this module into a project is by downloading it during the project configuration using the file(DOWNLOAD) function:

file(
  DOWNLOAD https://github.com/threeal/CheckWarning.cmake/releases/download/v3.2.0/CheckWarning.cmake
    ${CMAKE_BINARY_DIR}/cmake/CheckWarning.cmake
  EXPECTED_MD5 8f9c3170e816ba99a3ddc6848a8456f0)

include(${CMAKE_BINARY_DIR}/cmake/CheckWarning.cmake)

Alternatively, to support offline mode, this module can also be vendored directly into a project and included normally using the include function.

Check Warnings on Targets

Use the target_check_warning function to check for compiler warnings on a single target.

add_executable(main main.cpp)
target_check_warning(main)

If the TREAT_WARNINGS_AS_ERRORS option is specified, it treats all warnings from the target as errors. This will cause the build process to fail when a warning is triggered.

target_check_warning(main TREAT_WARNINGS_AS_ERRORS)

Alternatively, the add_check_warning function can be used to check for compiler warnings on all targets in the current directory.

add_check_warning(TREAT_WARNINGS_AS_ERRORS)

add_library(lib lib.cpp)
add_executable(main main.cpp)

Get Warning Flags

To retrieve the warning flags without adding them to a target, use the get_warning_flags function.

get_warning_flags(FLAGS)
message("Warning flags: ${FLAGS}")

Use the TREAT_WARNINGS_AS_ERRORS option to also include the flag that treats warnings as errors.

get_warning_flags(FLAGS TREAT_WARNINGS_AS_ERRORS)

API Reference

CHECK_WARNING_VERSION

This variable contains the version of the included CheckWarning.cmake module.

get_warning_flags

Retrieves warning flags based on the current compiler.

get_warning_flags(<output_var> [TREAT_WARNINGS_AS_ERRORS])

This function retrieves the warning flags for the current compiler and saves them to the variable <output_var>. It determines the compiler using the CMAKE_CXX_COMPILER_ID variable and retrieves the corresponding warning flags, as shown in the table below:

Compiler	Warning Flags
MSVC	/permissive- /W4 /EHsc
GNU or Clang	-Wall -Wextra -Wpedantic

If the TREAT_WARNINGS_AS_ERRORS option is specified, it appends the flag that treats warnings as errors, as shown in the table below:

Compiler	Flag
MSVC	/WX
GNU or Clang	-Werror

If the compiler is simulating another compiler, determined by the existence of the CMAKE_CXX_SIMULATE_ID variable, it will use that variable to determine the warning flags.

For compilers not listed in the table above, this function will trigger a fatal error, indicating that the compiler is unsupported.

target_check_warning

Enables warning checks on a specific target.

target_check_warning(<target> [TREAT_WARNINGS_AS_ERRORS])

This function enables warning checks on the <target> by appending warning flags from the get_warning_flags function to the compile options of that target. It is equivalent to calling the target_compile_options command on the target with the warning flags.

If the TREAT_WARNINGS_AS_ERRORS option is specified, it will also append the flag that treats warnings as errors.

add_check_warning

Enables warning checks on all targets in the current directory.

add_check_warning([TREAT_WARNINGS_AS_ERRORS])

This function enables warning checks on all targets in the current directory by appending warning flags from the get_warning_flags function to the default compile options. It is equivalent to calling the add_compile_options command with the warning flags.

If the TREAT_WARNINGS_AS_ERRORS option is specified, it will also append the flag that treats warnings as errors.

License

This project is licensed under the terms of the MIT License.

Copyright © 2023-2024 Alfi Maulana