Ignore/only show errors/warnings from certain directory using CMake

Basically the same as @ronkot's answer. But don't need add_subdirectory for certain directory, using set_source_files_properties with file(GLOB_RECURSE ...) also works.

file(GLOB_RECURSE SRC_DIR "SRC_DIR/*.c" "SRC_DIR/*.h")

set_source_files_properties(
  ${SRC_DIR}
  PROPERTIES
  COMPILE_FLAGS "-w"
)

Expanding on @ronkot answer, the recommended target-based approach would be:

target_compile_options(your_target SCOPE compiler-warning-options)

Where SCOPE is PUBLIC|INTERFACE|PRIVATE, and compiler-warning-options are actual compiler warning options, such as -Wall. See cmake's docs for more info.

In general, prefer a target-based approach with modern CMake (3.0+) rather than a directory-based approach.

You can set compiler warning options in CMake at least for certain target or certain files.

# For target
set_target_properties(your_project_name PROPERTIES COMPILE_FLAGS "...")

# For files
set_source_files_properties(
  ${list_of_your_files}
  PROPERTIES
  COMPILE_FLAGS "..."
)

It is also possible to set the options per-folder basis by separating your project as subproject, add it using add_subdirectory(your_project) and in your project CMakeLists.txt use add_definitions(...).

From CMake documentation:

add_definitions Adds flags to the compiler command line for sources in the current directory and below.