3.10 Installation Directory

During analysis and elaboration GHDL may read the std and ieee files. The location of these files is based on the prefix, which is (in priority order):

1. the --PREFIX= command line option
2. the GHDL_PREFIX environment variable
3. a built-in default path. It is a hard-coded path on GNU/Linux and the value of the ‘HKLM\Software\Ghdl\Install_Dir’ registry entry on Windows.

You should use the --dispconfig command (see Dispconfig command for details) to disp and debug installation problems.