CMP0070

Define file(GENERATE) behavior for relative paths.

CMake 3.10 and newer define that relative paths given to INPUT and OUTPUT arguments of file(GENERATE) are interpreted relative to the current source and binary directories, respectively. CMake 3.9 and lower did not define any behavior for relative paths but did not diagnose them either and accidentally treated them relative to the process working directory. Policy CMP0070 provides compatibility with projects that used the old undefined behavior.

This policy affects behavior of relative paths given to file(GENERATE). The OLD behavior for this policy is to treat the paths relative to the working directory of CMake. The NEW behavior for this policy is to interpret relative paths with respect to the current source or binary directory of the caller.

This policy was introduced in CMake version 3.10. CMake version 3.19.0-rc3 warns when the policy is not set and uses OLD behavior. Use the cmake_policy() command to set it to OLD or NEW explicitly.