cmake: Added ENABLE_STATIC_LIBS option

- Allows building static libraries
- For users calling find_package(UHD), provides extra options
  for building apps statically linking UHD.
- Updated the init_usrp example to link UHD statically.

1 files changed, 28 insertions, 4 deletions

diff --git a/host/examples/init_usrp/CMakeLists.txt b/host/examples/init_usrp/CMakeLists.txt
index 420e79993..3560dbd45 100644
--- a/host/examples/init_usrp/CMakeLists.txt
+++ b/host/examples/init_usrp/CMakeLists.txt
@@ -1,5 +1,5 @@
 #
-# Copyright 2014 Ettus Research LLC
+# Copyright 2014-2015 Ettus Research LLC
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -18,6 +18,11 @@
 cmake_minimum_required(VERSION 2.8)
 
 ### Set up build environment ##################################################
+# Choose a static or shared-library build (shared is default, and static will
+# probably need some special care!)
+# Set this to ON in order to link a static build of UHD:
+option(UHD_USE_STATIC_LIBS OFF)
+
 # This example also requires Boost:
 set(BOOST_REQUIRED_COMPONENTS
     program_options
@@ -35,10 +40,10 @@ endif(MSVC)
 find_package(Boost "1.46" REQUIRED ${BOOST_REQUIRED_COMPONENTS})
 
 # To add UHD as a dependency to this project, add a line such as this:
-find_package(UHD "3.7.1" REQUIRED)
+find_package(UHD "3.8.0" REQUIRED)
 # The version in  ^^^^^  here is a minimum version.
 # To specify an exact version:
-#find_package(UHD 3.7.1 EXACT REQUIRED)
+#find_package(UHD 3.8.1 EXACT REQUIRED)
 
 ### Configure Compiler ########################################################
 include_directories(
@@ -49,7 +54,26 @@ link_directories(${Boost_LIBRARY_DIRS})
 
 ### Make the executable #######################################################
 add_executable(init_usrp init_usrp.cpp)
-target_link_libraries(init_usrp ${UHD_LIBRARIES} ${Boost_LIBRARIES})
 
+# Shared library case: All we need to do is link against the library, and
+# anything else we need (in this case, some Boost libraries):
+if(NOT UHD_USE_STATIC_LIBS)
+    message(STATUS "Linking against shared UHD library.")
+    target_link_libraries(init_usrp ${UHD_LIBRARIES} ${Boost_LIBRARIES})
+# Shared library case: All we need to do is link against the library, and
+# anything else we need (in this case, some Boost libraries):
+else(NOT UHD_USE_STATIC_LIBS)
+    message(STATUS "Linking against static UHD library.")
+    target_link_libraries(init_usrp
+        # We could use ${UHD_LIBRARIES}, but linking requires some extra flags,
+        # so we use this convenience variable provided to us
+        ${UHD_STATIC_LIB_LINK_FLAG}
+        # Also, when linking statically, we need to pull in all the deps for
+        # UHD as well, because the dependencies don't get resolved automatically
+        ${UHD_STATIC_LIB_DEPS}
+    )
+endif(NOT UHD_USE_STATIC_LIBS)
+
+### Once it's built... ########################################################
 # Here, you would have commands to install your program.
 # We will skip these in this example.