1.\" $OpenBSD: library-specs.7,v 1.13 2018/07/09 15:34:10 jmc Exp $ 2.\" 3.\" Copyright (c) 2001-2010 Marc Espie 4.\" 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd $Mdocdate: July 9 2018 $ 28.Dt LIBRARY-SPECS 7 29.Os 30.Sh NAME 31.Nm library-specs 32.Nd shared library name specifications 33.Sh DESCRIPTION 34Each 35.Ev WANTLIB 36item in the ports tree conforms to 37.Bd -literal -offset indent 38[path/]libname[=major[.minor]] 39.Ed 40.Pp 41or 42.Bd -literal -offset indent 43[path/]libname[>=major[.minor]] 44.Ed 45.Pp 46All libraries that a package needs must be mentioned in that list. 47Except for system and X11 libraries, they all must be reachable through 48.Ev LIB_DEPENDS 49and 50.Ev RUN_DEPENDS , 51directly, or indirectly through recursive dependencies. 52.Pp 53Conversely, the ports tree 54uses 55.Ev WANTLIB 56to check whether a given 57.Ev LIB_DEPENDS 58will be required at runtime for shared libraries, and thus turn it into a 59.Cm @depend 60line 61.Po 62see 63.Xr pkg_create 1 64.Pc . 65.Pp 66The package system will embed correct dependency checks in the built 67package in the form of 68.Cm @wantlib 69lines, according to the normal shared library semantics: any library with 70the same major number, and a greater or equal minor number will do. 71.Pp 72Note that static libraries can only satisfy a library specification if 73no shared library has been found. 74Thus, if WANTLIB = foo>=5, and both libfoo.so.4.0 and libfoo.a are present, 75the check will fail. 76.Pp 77Therefore, porters must strive to respect correct shared library semantics 78in their own ports: by bumping the minor number each time the interface is 79augmented, and by bumping the major number each time the interface changes. 80Note that adding functions to a library is an interface augmentation. 81Removing functions is an interface change. 82.Pp 83The major.minor components of the library specification are used only as a 84build-time check, the run-time checks are computed by 85.Xr port-resolve-lib-helper 1 . 86For 87.Sq libname>=major[.minor] , 88any library which is more recent than the given major.minor version will 89do. 90If a specific major number is needed, use the form 91.Sq libname=major[.minor] . 92If the minor component is left empty, any minor will do. 93If both components are left empty, any version will do. 94.Pp 95Most specifications won't mention a 96.Pa path : 97.Xr port-resolve-lib-helper 1 98will look in the default 99.Xr ldconfig 8 100path automatically, namely 101.Pa /usr/local/lib , 102.Pa /usr/X11R6/lib , 103.Pa /usr/lib . 104It is generally a bad idea to put libraries elsewhere as they won't be 105reached directly. 106.Pp 107However, distinct ports may install different major versions of the same 108library in 109.Pa /usr/local/lib , 110and disambiguate the build by creating a link in a separate directory, 111and specifying the right options to the linker. 112.Pp 113These libraries will require a 114.Pa path 115component in the corresponding 116.Ev WANTLIB 117to make sure the right library is resolved. 118This path is rooted under 119.Pa /usr/local . 120For instance, to refer to 121.Pa /usr/local/lib/qt3/libqt-mt.so.33.0 , 122one would use 123.Sq lib/qt3/qt-mt>=33 . 124.Sh SEE ALSO 125.Xr check-lib-depends 1 , 126.Xr ld 1 , 127.Xr ld.so 1 , 128.Xr pkg_add 1 , 129.Xr port-resolve-lib-helper 1 , 130.Xr bsd.port.mk 5 , 131.Xr packages 7 , 132.Xr packages-specs 7 , 133.Xr ports 7 , 134.Xr ldconfig 8 135.Sh HISTORY 136Full support for library specifications first appeared in 137.Ox 3.1 . 138The format of specifications changed slightly to include 139.Sq >= 140before 141.Ox 4.0 . 142The interactions between 143.Ev LIB_DEPENDS 144and 145.Ev WANTLIB 146were modified and clarified for 147.Ox 4.8 . 148The format of specifications changed again before 149.Ox 4.9 150to remove extra noise. 151