Add custom build step in CMake

Question

I'm trying to add a custom build step in CMake that generates some files. I haven't found a description how it works. I have an project where source, header & implementation files have to be generated by ODB for C++. ODB takes class headers as arguments and generates source files that I want to use in my project. Right now I have the following command in my CMakeLists.txt: ``` add_custom_command(TARGET ${PROJECT_NAME} PRE_BUILD COMMAND odb -o /home/david/dev/ --std c++11 -I/home/david/dev/ -d sqlite --generate- query --generate-schema ${PROMOTER_LIB_PREFIX}/entities/person.hpp DEPENDS ${PROJECT_NAME} VERBATIM ) ``` For a file `person.hpp` ODB should generate `person-odb.hxx`, `person-odb.cxx`, `person-odb.ixx` but the CMake command I''ve used doesn't generate anything. In a terminal this command works fine. What am I doing wrong? EDIT: The problem can be solved by adding the following lines: ``` set(FAKE_TARGET fakeTarget) add_custom_target(fakeTarget odb -o /home/david/dev/ --std c++…

Accepted Answer

For me, with something similar, I just use :

```
add_custom_command(TARGET ${PROJECT_NAME}
    PRE_BUILD
    COMMAND odb -o /home/david/dev/ --std c++11 -I/home/david/dev/ -d sqlite --generate-    query --generate-schema ${PROMOTER_LIB_PREFIX}/entities/person.hpp
)
```

We don't use `DEPENDS` or `VERBATIM`.

The `DEPENDS` option specify that the command must be executed only after that the project you gave to this option is built.

EDIT :

Note that the PRE_BUILD option is only supported on Visual Studio 7 or later. For all other generators PRE_BUILD will be treated as PRE_LINK.

Maybe that's why it doesn't work for you.

A work around could be (a bit ugly) :

- Create a fake project

- Add your custom command on it as POST_BUILD

- Make you current project dependent on the fake one

Add custom build step in CMake

Solution

Problem