LIBRARY-SPECS(7) OpenBSD Reference Manual LIBRARY-SPECS(7)NAMElibrary-specs - shared library name specifications
DESCRIPTION
Each WANTLIB item in the ports tree conforms to
[path/]libname[=major[.minor]]
or
[path/]libname[>=major[.minor]]
All libraries that a package needs must be mentioned in that list.
Except for system and X11 libraries, they all must be reachable through
LIB_DEPENDS and RUN_DEPENDS, directly, or indirectly through recursive
dependencies.
Conversely, the ports tree uses WANTLIB to check whether a given
LIB_DEPENDS will be required at runtime for shared libraries, and thus
turn it into a @depend line (see pkg_create(1)).
The package system will embed correct dependency checks in the built
package in the form of @wantlib lines, according to the normal shared
library semantics: any library with the same major number, and a greater
or equal minor number will do.
Note that static libraries can only satisfy a library specification if no
shared library has been found. Thus, if WANTLIB = foo>=5, and both
libfoo.so.4.0 and libfoo.a are present, the check will fail.
Therefore, porters must strive to respect correct shared library
semantics in their own ports: by bumping the minor number each time the
interface is augmented, and by bumping the major number each time the
interface changes. Note that adding functions to a library is an
interface augmentation. Removing functions is an interface change.
The major.minor components of the library specification are used only as
a build-time check, the run-time checks are computed by resolve-lib(1).
For `libname>=major[.minor]', any library which is more recent than the
given major.minor version will do. If a specific major number is needed,
use the form `libname=major[.minor]'. If the minor component is left
empty, any minor will do. If both components are left empty, any version
will do.
If a given architecture does not support shared libraries, all
LIB_DEPENDS will be turned into simple BUILD_DEPENDS checks, and so,
failure to mention RUN_DEPENDS if the port needs anything beyond
libraries from the dependent port will lead to strange errors on such
architectures.
Most specifications won't mention a path: resolve-lib(1) will look in the
default ldconfig(8) path automatically, namely /usr/local/lib,
/usr/X11R6/lib, /usr/lib. It is generally a bad idea to put libraries
elsewhere as they won't be reached directly.
However, distinct ports may install different major versions of the same
library in /usr/local/lib, and disambiguate the build by creating a link
in a separate directory, and specifying the right options to the linker.
These libraries will require a path component in the corresponding
WANTLIB to make sure the right library is resolved. This path is rooted
under /usr/local. For instance, to refer to
/usr/local/lib/qt3/libqt-mt.so.33.0, one would use `lib/qt3/qt-mt>=33'.
SEE ALSOcheck-lib-depends(1), ld(1), ld.so(1), pkg_add(1), resolve_lib(1),
bsd.port.mk(5), packages(7), packages-specs(7), ports(7), ldconfig(8)HISTORY
Full support for library specifications first appeared in OpenBSD 3.1.
The format of specifications changed slightly to include `>=' before
OpenBSD 4.0. The interactions between LIB_DEPENDS and WANTLIB were
modified and clarified for OpenBSD 4.8. The format of specifications
changed again before OpenBSD 4.9 to remove extra noise.
OpenBSD 4.9 November 15, 2010 OpenBSD 4.9
