[CMake] cmake documentation incomplete

[Vania Joloboff]

Hi,

The cmake documentation says there are two alternatives
to start cmake

cmake [<options>] (<path-to-source> | <path-to-existing-build>)

But it does not explain nowhere the difference between the two...
Does the path-to-existing-build retrieve itself the source dir
and start like if it were invoked with path-to-source
from path-to-existing-build working directory ?

Vania