Library projects are projects whose object code is placed in a library. (Note that this facility is not yet supported on all platforms)
To create a library project, you need to define in its project file
two project-level attributes:
Additionally, you may define the library-related attributes
Library_Name attribute has a string value. There is no restriction
on the name of a library. It is the responsability of the developer to
choose a name that will be accepted by the platform. It is recommanded to
choose names that could be Ada identifiers; such names are almost guaranteed
to be acceptable on all platforms.
Library_Dir attribute has a string value that designates the path
(absolute or relative) of the directory where the library will reside.
It must designate an existing directory, and this directory must be
different from the project's object directory. It also needs to be writable.
Library_Dir are specified and
are legal, then the project file defines a library project. The optional
library-related attributes are checked only for such project files.
Library_Kind attribute has a string value that must be one of the
following (case insensitive):
"relocatable". If this attribute is not specified, the library is a
static library, that is an archive of object files that can be potentially
linked into an static executable. Otherwise, the library may be dynamic or
relocatable, that is a library that is loaded only at the start of execution.
Depending on the operating system, there may or may not be a distinction
between dynamic and relocatable libraries. For Unix and VMS Unix there is no
If you need to build both a static and a dynamic library, you should use two different object directories, since in some cases some extra code needs to be generated for the latter. For such cases, it is recommended to either use two different project files, or a single one which uses external variables to indicate what kind of library should be build.
Library_Version attribute has a string value whose interpretation
is platform dependent. It has no effect on VMS and Windows. On Unix, it is
used only for dynamic/relocatable libraries as the internal name of the
"soname"). If the library file name (built from the
Library_Name) is different from the
Library_Version, then the
library file will be a symbolic link to the actual file whose name will be
Example (on Unix):
project Plib is Version := "1"; for Library_Dir use "lib_dir"; for Library_Name use "dummy"; for Library_Kind use "relocatable"; for Library_Version use "libdummy.so." & Version; end Plib;
Directory lib_dir will contain the internal library file whose name will be libdummy.so.1, and libdummy.so will be a symbolic link to libdummy.so.1.
When gnatmake detects that a project file is a library project file, it will check all immediate sources of the project and rebuild the library if any of the sources have been recompiled.
When a library is built or rebuilt, an attempt is made to delete all files in the library directory. All ALI files will also be copied from the object directory to the library directory. To build executables, gnatmake will use the library rather than the individual object files. The copy of the ALI files are made read-only.