[CMake] file(COPY) is copying even if file hasn't changed

[Robert Dailey]

Oh also file(INSTALL) does the same thing; the "Installing:" message
gets printed each time for the same file, and never says that it is
"up to date".

On Wed, Jul 19, 2017 at 4:04 PM, Robert Dailey <rcdailey.lists at gmail.com> wrote:
> According to the documentation for file(COPY) [1]: "Copying preserves
> input file timestamps, and optimizes out a file if it exists at the
> destination with the same timestamp"
>
> However this is not the case. My host OS is Windows 10 and I'm using
> CMake 3.9.0-rc5. Each time my CMakeLists.txt is run, the file(COPY) is
> copying over the file even if it didn't change. The "date modified"
> timestamp for the destination file is updated. I do not want the copy
> to occur if the source file has not changed (this appears to be the
> intended behavior based on the documentation).
>
> Am I understanding this correctly or is this a bug?
>
> [1]: https://cmake.org/cmake/help/latest/command/file.html