From d5a4d1fb9c03a2648529c9ae196ea25cdf000634 Mon Sep 17 00:00:00 2001
From: Ulysses Apokin <ulysses@altlinux.org>
Date: Fri, 21 Nov 2025 10:32:22 +0300
Subject: [PATCH] Added versioning for shared libraries.

According to the packaging policies for shared libraries in Linux,
shared libraries should look like this:
libfoo.so.${MAJOR}.${MINOR}.${PATCH}

The following symlinks to this library should also be created:
libfoo.so .${MAJOR} -> libfoo.so .${MAJOR}.${MINOR}.${PATCH}
libfoo.so -> libfoo.so .${MAJOR}.${MINOR}.${PATCH}

In this case, the libfoo library package contains the following files:
The library itself: libfoo.so .${MAJOR}.${MINOR}.${PATCH}
As well as a symlink to it, which contains the library name and the ABI
version.:
libfoo.so.${MAJOR}

The following symlink is placed in the libfoo-devel package:
libfoo.so

This is the standard packaging method for many distributions.
Look:
https://docs.fedoraproject.org/en-US/packaging-guidelines/#_shared_libraries
https://www.debian.org/doc/debian-policy/ch-sharedlibs.html

Currently, when using the cmake options EIGEN_BUILD_BLAS=ON and
EIGEN_BUILD_LAPACK=ON, libraries are being built libeigen_blas.so and
libeigen_lapack.so . They do not have an ABI specific, which is not
suitable for packaging these libraries in distributions without
violating the policy.
---
 CMakeLists.txt        | 18 +++++++++---------
 blas/CMakeLists.txt   |  4 +++-
 lapack/CMakeLists.txt |  4 +++-
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 36912bcde..8bbab78c6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -100,19 +100,19 @@ endif()
 file(READ "${PROJECT_SOURCE_DIR}/Eigen/Version" _eigen_version_header)
 if (NOT DEFINED EIGEN_WORLD_VERSION)
   string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen_world_version_match "${_eigen_version_header}")
-  set(EIGEN_WORLD_VERSION "${CMAKE_MATCH_1}")
+  set(EIGEN_WORLD_VERSION "${CMAKE_MATCH_1}" CACHE STRING "")
 endif()
 if (NOT DEFINED EIGEN_MAJOR_VERSION)
   string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen_major_version_match "${_eigen_version_header}")
-  set(EIGEN_MAJOR_VERSION "${CMAKE_MATCH_1}")
+  set(EIGEN_MAJOR_VERSION "${CMAKE_MATCH_1}" CACHE STRING "")
 endif()
 if (NOT DEFINED EIGEN_MINOR_VERSION)
   string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen_minor_version_match "${_eigen_version_header}")
-  set(EIGEN_MINOR_VERSION "${CMAKE_MATCH_1}")
+  set(EIGEN_MINOR_VERSION "${CMAKE_MATCH_1}" CACHE STRING "")
 endif()
 if (NOT DEFINED EIGEN_PATCH_VERSION)
   string(REGEX MATCH "define[ \t]+EIGEN_PATCH_VERSION[ \t]+([0-9]+)" _eigen_patch_version_match "${_eigen_version_header}")
-  set(EIGEN_PATCH_VERSION "${CMAKE_MATCH_1}")
+  set(EIGEN_PATCH_VERSION "${CMAKE_MATCH_1}" CACHE STRING "")
 endif()
 if (NOT DEFINED EIGEN_PRERELEASE_VERSION)
   set(EIGEN_PRERELEASE_VERSION "dev")
@@ -134,18 +134,18 @@ endif()
 if (NOT DEFINED EIGEN_BUILD_VERSION AND DEFINED EIGEN_GIT_REVNUM)
   string(SUBSTRING "${EIGEN_GIT_REVNUM}" 0 8 EIGEN_BUILD_VERSION)
 else()
-  set(EIGEN_BUILD_VERSION "")
+  set(EIGEN_BUILD_VERSION "" CACHE STRING "")
 endif()
 
 # The EIGEN_VERSION_NUMBER must be of the form <major.minor.patch>.
 # The EIGEN_VERSION_STRING can contain the preprelease/build strings.
-set(EIGEN_VERSION_NUMBER "${EIGEN_MAJOR_VERSION}.${EIGEN_MINOR_VERSION}.${EIGEN_PATCH_VERSION}")
-set(EIGEN_VERSION_STRING "${EIGEN_VERSION_NUMBER}")
+set(EIGEN_VERSION_NUMBER "${EIGEN_MAJOR_VERSION}.${EIGEN_MINOR_VERSION}.${EIGEN_PATCH_VERSION}" CACHE STRING "")
+set(EIGEN_VERSION_STRING "${EIGEN_VERSION_NUMBER}" CACHE STRING "")
 if (NOT "x${EIGEN_PRERELEASE_VERSION}" STREQUAL "x")
-  set(EIGEN_VERSION_STRING "${EIGEN_VERSION_STRING}-${EIGEN_PRERELEASE_VERSION}")
+  set(EIGEN_VERSION_STRING "${EIGEN_VERSION_STRING}-${EIGEN_PRERELEASE_VERSION}" CACHE STRING "")
 endif()
 if (NOT "x${EIGEN_BUILD_VERSION}" STREQUAL "x")
-  set(EIGEN_VERSION_STRING "${EIGEN_VERSION_STRING}+${EIGEN_BUILD_VERSION}")
+  set(EIGEN_VERSION_STRING "${EIGEN_VERSION_STRING}+${EIGEN_BUILD_VERSION}" CACHE STRING "")
 endif()
 
 
diff --git a/blas/CMakeLists.txt b/blas/CMakeLists.txt
index 45488d73d..c8a28851b 100644
--- a/blas/CMakeLists.txt
+++ b/blas/CMakeLists.txt
@@ -21,7 +21,9 @@ list(APPEND EIGEN_BLAS_TARGETS eigen_blas_static)
 if (EIGEN_BUILD_SHARED_LIBS)
   add_library(eigen_blas SHARED ${EigenBlas_SRCS} "eigen_blas.def")
   target_compile_definitions(eigen_blas PUBLIC "EIGEN_BLAS_BUILD_DLL")
-  set_target_properties(eigen_blas PROPERTIES CXX_VISIBILITY_PRESET hidden)
+  set_target_properties(eigen_blas PROPERTIES CXX_VISIBILITY_PRESET hidden
+    VERSION ${EIGEN_VERSION_NUMBER}
+    SOVERSION ${EIGEN_MAJOR_VERSION})
   list(APPEND EIGEN_BLAS_TARGETS eigen_blas)
 endif()
 
diff --git a/lapack/CMakeLists.txt b/lapack/CMakeLists.txt
index d837fff96..51bb45516 100644
--- a/lapack/CMakeLists.txt
+++ b/lapack/CMakeLists.txt
@@ -110,7 +110,9 @@ if (EIGEN_BUILD_SHARED_LIBS)
   # Build LAPACK but link BLAS.
   target_compile_definitions(eigen_lapack PUBLIC "EIGEN_BLAS_LINK_DLL" "EIGEN_LAPACK_BUILD_DLL")
   target_link_libraries(eigen_lapack  eigen_blas)
-  set_target_properties(eigen_lapack PROPERTIES CXX_VISIBILITY_PRESET hidden)
+  set_target_properties(eigen_lapack PROPERTIES CXX_VISIBILITY_PRESET hidden
+    VERSION ${EIGEN_VERSION_NUMBER}
+    SOVERSION ${EIGEN_MAJOR_VERSION})
   list(APPEND EIGEN_LAPACK_TARGETS eigen_lapack)
 endif()
 
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