Installing a library (GNAT User’s Guide for Native Platforms)

#### 3.9.2.2 Installing a library ¶

If you use project files, library installation is part of the library build process (see the ‘Installing a Library with Project Files’ section of the ‘GNAT Project Manager’ chapter of the GPRbuild User’s Guide).

When you’re not able to use project files for some reason, you can also install the library so that the sources needed to use the library are on the Ada source path and the ALI files & libraries be on the Ada Object path (see Search Paths and the Run-Time Library (RTL)), but we don’t recommend doing this. Alternatively, the system administrator can place general-purpose libraries in the default compiler paths, by specifying the libraries’ location in the configuration files `ada_source_path` and `ada_object_path`. These configuration files must be located in the GNAT installation tree at the same place as the `gcc` spec file. The location of the `gcc` spec file can be determined as follows:

    $ gcc -v

The configuration files mentioned above have a simple format: each line must contain one unique directory name. Those names are added to the corresponding path in their order of appearance in the file. The names can be either absolute or relative; in the latter case, they are relative to where theses files are located.

The files `ada_source_path` and `ada_object_path` might not be present in a GNAT installation, in which case, GNAT looks for its run-time library in the directories `adainclude` (for the sources) and `adalib` (for the objects and `ALI` files). When the files exist, the compiler does not look in `adainclude` and `adalib`, and thus the `ada_source_path` file must contain the location for the GNAT run-time sources (which can simply be `adainclude`). In the same way, the `ada_object_path` file must contain the location for the GNAT run-time objects (which can simply be `adalib`).

You can also specify a new default path to the run-time library at compilation time with the `--RTS=rts-path` switch. You can thus choose the run-time library you want your program to be compiled with. This switch is recognized by `gcc`, `gnatmake`, `gnatbind`, `gnatls`, and all project aware tools.

You can install a library before or after the standard GNAT library by selecting the ordering the lines in the configuration files. In general, a library must be installed before the GNAT library if it redefines any part of it.