Most external project commands support generator expressions.
INSTALL_DIR isn’t used by CMake directly but instead used as placeholder in commands which support generator expressions. Documentation doesn’t mention and from experimental results it seems that using generator expressions inside
INSTALL_DIR doesn’t work as CMake tries to validate the path without expanding generator expressions. In case of
INSTALL_DIR workaround is not using <INSTALL_DIR> and specifying generator expression directly, but in case BINARY_DIR where the project gets built such workaround doesn’t work.
Is there a reason for not supporting generator expressions for external project directories? Am I using external projects incorrectly?
My motivation is that using “Visual Studio” generator executables get placed in directory that depends on Config (Release or Debug). I want to install the dlls from external project in the same directory so that development build can be run.