rerunning configure_file when the input file changes.

Code
1

When cmake runs the first time I am able to generate a file using the following:

configure_file(foo.cpp.in foo.cpp)

That works great. But if foo.cpp.in changes I would like foo.cpp to be regenerated. If I touch foo.cpp.in cmake will rerun but foo.cpp is not regenerated.

I was thinking that perhaps a custom command could be used but not sure what the command would be given I want to use configure_file.

Any pointers??? Thanks.

2

Touching the file is not enough to relaunch configuke_file() as described in the documentation:

The generated file is modified and its timestamp updated on subsequent cmake runs only if its content is changed.

3

Thanks for that pointer. I did not see that detail. I modified the file and the new files are generated.

4

In general to handle more advanced cases, like where file1 is read by CMake to configure_file() for file2, you can use directory property CONFIGURE_DEPENDS.