Simple SOVERSION (#3066)

Co-authored-by: Bas Couwenberg <sebastic@xs4all.nl>

CMakeLists.txt

@@ -111,13 +111,8 @@ message(STATUS "Configuring PROJ:")
 ################################################################################
 include(ProjVersion)
 proj_version(MAJOR 9 MINOR 0 PATCH 0)
-# Use libtool convention to build the CMake's VERSION and SOVERSION
-# See https://github.com/pvanhoof/dir-examples#cmake-in-the-cmake-example
-set(PROJ_LIBTOOL_CURRENT    25)
-set(PROJ_LIBTOOL_REVISION   0)
-set(PROJ_LIBTOOL_AGE        0)
-math(EXPR PROJ_API_VERSION "${PROJ_LIBTOOL_CURRENT} - ${PROJ_LIBTOOL_AGE}")
-set(PROJ_BUILD_VERSION "${PROJ_API_VERSION}.${PROJ_LIBTOOL_AGE}.${PROJ_LIBTOOL_REVISION}")
+set(PROJ_SOVERSION 25)
+set(PROJ_BUILD_VERSION "${PROJ_SOVERSION}.${PROJ_VERSION}")
 
 ################################################################################
 # Build features and variants

HOWTO-RELEASE

@@ -33,20 +33,10 @@ list. The PROJ PSC guidelines describes the rules for passing a motion.
 In case of a un-planned maintenance release, make sure that version numbers are
 properly updated: see 3.1
 
-Determine the ABI version number. It consists of "current:revision:age". Follow
-the steps below to determine the values in CMakeLists.txt:
-
-   - If the library source code has changed at all since the last update,
-     then increment PROJ_LIBTOOL_REVISION (c:r:a becomes c:r+1:a).
-
-   - If any interfaces have been added, removed, or changed since the last
-     update, increment PROJ_LIBTOOL_CURRENT and set PROJ_LIBTOOL_REVISION to 0.
-
-   - If any interfaces have been added since the last public release, then
-     increment PROJ_LIBTOOL_AGE.
-
-   - If any interfaces have been removed since the last public release, then
-     set PROJ_LIBTOOL_AGE to 0.
+For each release version, increment PROJ_SOVERSION in CMakeLists.txt if the 
+ABI is not backwards compatible, i.e. any interfaces have been removed, or 
+changed since the last release. See also:
+https://community.kde.org/Policies/Binary_Compatibility_Issues_With_C%2B%2B
 
 *Commit the changes to master.*
 

src/lib_proj.cmake

@@ -402,21 +402,21 @@ target_include_directories(proj INTERFACE
 if(WIN32)
   set_target_properties(proj
     PROPERTIES
-    VERSION "${${PROJECT_NAME}_BUILD_VERSION}"
+    VERSION "${PROJ_VERSION}"
     OUTPUT_NAME "${PROJ_CORE_TARGET_OUTPUT_NAME}"
     ARCHIVE_OUTPUT_NAME proj
     CLEAN_DIRECT_OUTPUT 1)
 elseif(BUILD_FRAMEWORKS_AND_BUNDLE)
   set_target_properties(proj
     PROPERTIES
-    VERSION "${${PROJECT_NAME}_BUILD_VERSION}"
+    VERSION "${PROJ_VERSION}"
     INSTALL_NAME_DIR ${PROJ_INSTALL_NAME_DIR}
     CLEAN_DIRECT_OUTPUT 1)
 else()
   set_target_properties(proj
     PROPERTIES
-    VERSION "${${PROJECT_NAME}_BUILD_VERSION}"
-    SOVERSION "${${PROJECT_NAME}_API_VERSION}"
+    VERSION "${PROJ_BUILD_VERSION}"
+    SOVERSION "${PROJ_SOVERSION}"
     CLEAN_DIRECT_OUTPUT 1)
 endif()