Man page - dh_ada_library(1)

Packages contains this manual

Package: dh-ada-library
apt-get install dh-ada-library

Manuals in package:

dh_ada_library(1)

Documentations in package:

dh-ada-library

Manual

DH_ADA_LIBRARY

NAME
SYNOPSIS
DESCRIPTION
Runtime library package
Development package (-dev)
Files that are not installed
REMARKS
OPTIONS
EXAMPLES
VERSIONS
SEE ALSO
AUTHOR

NAME

dh_ada_library - help packaging Ada libraries for Debian

SYNOPSIS

dh_ada_library [ debhelper options ]

DESCRIPTION

dh_ada_library is a debhelper program that handles some common tasks in packaging libraries written in the Ada programming language.

The difficult work is to convince the upstream build system to produce both a static and a relocatable library in a row (during the dh_auto_configure and dh_auto_build steps), then to install these under debian/tmp/ with the directory structure described by the Debian Policy for Ada ( dh_auto_install ). The /usr/share/ada/packaging.mk Makefile snippet, part of the same dh-ada-library package, may help for that. It contains lots of comments describing its usage.

Once the files are installed, dh_ada_library is in charge of dispatching them to the specific package temporary directories. It is enabled by the presence of the dh-sequence-ada-library virtual package in the Build-Depends-Arch field of the debian/control file. For a while, you should in addition depend on the explicit dh-ada-library concrete package and require at least version 9, because this version introduces incompatible changes, and virtual packages cannot receive version restrictions.

At start, it parses debian/control to find Ada libraries: architecture-dependent packages, named lib name -dev , depending on ${ada:Depends} and providing ${ada:Provides} .

For each one, there must also be a runtime library package, named from the shared object name as described in section 8 of the Debian Policy (usually lib name - SOversion ).

For a description of DEB_HOST_MULTIARCH , see dpkg-architecture (1). The installation directories ( DEB_ADA_SOURCE_DIR , DEB_LIB_DIR , DEB_ADA_LIB_INFO_DIR and DEB_GNAT_PROJECT_DIR ) are defined in the Debian Policy, their current values are available via packaging.mk .

Runtime library package

The following files are copied from debian/tmp/ to debian/lib name - SOversion / .
DEB_LIB_DIR / shared library

The concrete file containing the shared library. It is found by following the debian/tmp/ DEB_LIB_DIR /lib name .so symbolic link.

DEB_LIB_DIR / SOname

The shared object name ( SOname ) is extracted from the binary data in the shared library, and may differ from the file name. If so, this symbolic link also refers to the shared library and is also installed (for ldconfig, see the Debian Policy for details).

dh_link later removes the redundant path components like lib/.. .

Versions before 8.1 were ignoring the SOname/Library_Version, and guessing it from the SOversion in the Debian package name. Patches caused by this unfortunate decision can now be unapplied.

Development package (-dev)

The following files are copied from debian/tmp/ to debian/lib name / .
DEB_ADA_LIB_INFO_DIR / name / * .ali

The GNAT Ada Library Information files files created along the objects when building the shared library.

dh_fixperms later checks that their permissions are 444.

In order to improve build reproducibility, -f*-prefix-map compiler flags are removed from them.

DEB_ADA_SOURCE_DIR / name / *

The sources, Ada or not, should all be in a single directory.

DEB_LIB_DIR /lib name .a

The static archive.

DEB_GNAT_PROJECT_DIR / name .gpr

This standalone library GNAT project intended for use after installation.

If the library was built with gprbuild and another GNAT project, the gprinstall tool can generate such a standalone project with the correct Languages , Linker_Switches in the Linker package, imports ( with ), source file renamings... Else, the maintainer must write a new project, or more accurately generate it because DEB_HOST_MULTIARCH cannot be hardcoded. If so, it is recommended to also substitute the path variables set by /usr/share/ada/packaging.mk , in case the directory structure ever has to change (again).

In order to improve build reproducibility, -f*-prefix-map compiler flags are removed (for examples because gprbuild has copied variables like ADAFLAGS from the build project).

DEB_LIB_DIR /lib name .so

The development symbolic link is installed here, but dangling because the concrete shared library is in the runtime library package.

dh_link later removes the redundant path components like lib/.. .

ada:Depends

This debhelper substitution variable is created for inclusion in the Depends field of the lib name -dev package in debian/control . Its value contains the following dependencies.
lib name - SOversion (= ${binary:Version})

The development package needs the same version of the runtime library package because of the dangling symbolic link.

gnat (>= DEB_GNAT_VERSION ), gnat (<< DEB_GNAT_VERSION + 1 )

The development package requires the default Ada compiler in order to ensure the compatibility with all other Ada packages.

gnat- DEB_GNAT_VERSION - HASH

This virtual package reflects the (host) version of the run-time library used during the build.

More items are added as described in the next sections in order to reflect the dependencies across Ada library packages.

ada:Provides

This debhelper substitution variable is created for inclusion in the Provides field of the lib name -dev package in debian/control .

It only contains lib name -dev- HASH , where HASH is a 32 bit XOR of all checksums in the .ali files (8 lowercase hexadecimal digits).

Imported projects

In addition, dh_ada_library searches debian/tmp/ DEB_GNAT_PROJECT_DIR / name .gpr for imported projects ( with ). For each imported library project dep .gpr , a dependency is added into ada:Depends .

If lib dep -dev is built from the same source package, the dependency is lib dep -dev (= ${binary:Version}) , ensuring that all static libraries are compiled with compatible options. Such a restriction is more specific than a hash suffix.

If lib dep -dev is not built from the same source but is installed on the system, in other words if it is listed in Build-Depends , the dependency is on the lib dep -dev- hash virtual package provided by the installed concrete lib dep -dev . It prevents later installation of an update of lib dep -dev modifying its ALI checksums.

Remaining projects trigger a warning, because the maintainer will need to find the right dependency.

Versions before 8.1 were guessing more dependencies from Linker’Linker_Options . This was often wrong, for no benefit since C -dev packages carry no version and can be hard-coded in debian/control .

Files that are not installed

The following files, if they exist under debian/tmp/ , are ignored but marked as installed by dh_ada_library in order to prevent a false alert by dh_missing later, as if the files were listed in debian/not-installed .
usr/unwantedly_gprinstalled/

Please refer to /usr/share/ada/packaging.mk .

DEB_LIB_DIR /lib name .la

The Debian Policy recommends not to install libtool .la files.

REMARKS

It would be easy to fix the directory structure, and versions before 8.1 were doing exactly this, at the cost of generating a project with different paths. Now that gprinstall is almost capable of dealing with stagged installs, duplicating its job seems a waste of energy.

For now, DEB_ADA_SOURCE_DIR and DEB_GNAT_PROJECT_DIR are under /usr/share/ada/ . This implies that the -dev package cannot be declared Multi-Arch: same as the content of the project (and maybe of generated sources) will vary across architectures.

The Linker’Linker_Options attribute should rarely be needed. A dependency written in Ada should be described by an imported project, also handling .ali files. A dependency written in C should be listed in Library_Options when building a shared library, and in Linker’Linker_Options when using a static archive, but is not always required in Linker’Linker_Options for shared libraries. Until now, such options have only proved useful to light bindings importing C symbols from a specification or an inlined procedure. In a foo.pc file as read by pkg-config , they are named Libs , excluding -lfoo and Libs.private .

OPTIONS

Common debhelper command line options and environment variables are recognized.
--export-versions

This option is intended for support of packaging.mk . Print Makefile definitions for the variables described in it.

EXAMPLES

This stanza in debian/rules may help debugging.

override_dh_ada_library:
dh_ada_library -v"

VERSIONS

The version is composed of two numbers separated by a dot. The second one increases during a normal update, which supposedly fixes bugs, introduces compatible evolutions, or remove stuff unused since oldoldstable . A change in the first one announces an incompatibility requiring some users to modify their source package.

AUTHOR

Nicolas Boulenguez <nicolas@debian.org>