CMakeLists.txt: Add possibility to build library as shared

This adds the option to build the soem library also as shared object.
Note that the default is untouched, so by default, it will still build
a static library.

The [BUILD_SHARED_LIBS](https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html)
is the standard way of doing it, many tools use this semantics to influence
the output to be the desired type (whichever you want).

Signed-off-by: Matthias Schoepfer <matthias.schoepfer@googlemail.com>

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f9f67ab65b2ae125859c4ac0e630ac74627f0b56..bf30105eddb26d38ac6655aa78917ea2e63e7299 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,8 @@ if (CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
   set(CMAKE_INSTALL_PREFIX ${CMAKE_CURRENT_LIST_DIR}/install)
 endif()
 
+option(BUILD_SHARED_LIBS "Build using shared libraries" OFF)
+
 set(SOEM_INCLUDE_INSTALL_DIR include/soem)
 set(SOEM_LIB_INSTALL_DIR lib)
 
@@ -75,11 +77,16 @@ file(GLOB SOEM_HEADERS soem/*.h)
 file(GLOB OSAL_HEADERS osal/osal.h osal/${OS}/*.h)
 file(GLOB OSHW_HEADERS oshw/${OS}/*.h)
 
-add_library(soem STATIC
+add_library(soem
   ${SOEM_SOURCES}
   ${OSAL_SOURCES}
   ${OSHW_SOURCES}
   ${OSHW_EXTRA_SOURCES})
+
+if (BUILD_SHARED_LIBS)
+  set_target_properties(soem PROPERTIES VERSION ${PROJECT_VERSION} SOVERSION ${PROJECT_VERSION_MAJOR})
+endif(BUILD_SHARED_LIBS)
+
 target_link_libraries(soem ${OS_LIBS})
 
 target_include_directories(soem PUBLIC