From 8be6b24ae3046010e6b556a21d5e3aa89374826e Mon Sep 17 00:00:00 2001
From: mkoop <marian.koop@ni.com>
Date: Fri, 17 Feb 2023 16:14:21 +0100
Subject: [PATCH] extension: windows: Fixed linking extension example to
 uhd.lib

Symtom to observed
Example of how to use a (new) feature/behavior
---
 host/docs/extension.dox                       | 11 -----
 .../examples/extension_example/CMakeLists.txt | 45 ++++++++++++++++---
 2 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/host/docs/extension.dox b/host/docs/extension.dox
index 71f466fc1..e930ad056 100644
--- a/host/docs/extension.dox
+++ b/host/docs/extension.dox
@@ -14,17 +14,6 @@ example in the examples directory. It can be built by
 
 Depending on your UHD installation prefix root privileges may be required for `make install`.
 
-<b>Known issue</b>: 
-When using the Python API with an extension installed, `import uhd` may throw an error: 
-
-`Error: EnvironmentError: OSError: dlopen failed to load "/path/to/libextension.so"`
-
-If this occurs, please provide the LD_PRELOAD variable with the path to the uhdlib:
-
-export LD_PRELOAD=[UHD_PREFIX]/lib/libuhd.so
-
-Afterwards start Python again in the same commandline. 
-
 \section extension_capabilities Capabilities of the Extension Framework
 
 The Extension Framework attaches to multi_usrp and will work for all RFNoC-capable devices. 
diff --git a/host/examples/extension_example/CMakeLists.txt b/host/examples/extension_example/CMakeLists.txt
index 5cb094254..0f840f7e3 100644
--- a/host/examples/extension_example/CMakeLists.txt
+++ b/host/examples/extension_example/CMakeLists.txt
@@ -42,7 +42,7 @@ include(UHDBoost)
 
 # need these include and link directories for the build
 include_directories(
-    ${CMAKE_SOURCE_DIR}/include
+    ${CMAKE_CURRENT_SOURCE_DIR}/include
     ${Boost_INCLUDE_DIRS}
     ${UHD_INCLUDE_DIRS}
 )
@@ -55,16 +55,49 @@ list(APPEND extexample_sources
 )
 add_subdirectory(include)
 
-message(STATUS "UHD Module Path (to which the extension will be linked):")
-message(STATUS ${UHD_MODULE_PATH})
+message(STATUS ${PROJECT_NAME} " linking against library found at:")
+message(STATUS "  " ${UHD_LIB_PATH})
 
 ### Make the executable #######################################################
 add_library(extexample SHARED ${extexample_sources})
 
+##set(CMAKE_BUILD_TYPE "Release")
+message(STATUS "******************************************************************************")
+message(STATUS "* NOTE: When building your own app, you probably need all kinds of different  ")
+message(STATUS "* compiler flags. This is just an example, so it's unlikely these settings    ")
+message(STATUS "* exactly match what you require. Make sure to double-check compiler and     ")
+message(STATUS "* linker flags to make sure your specific requirements are included.          ")
+message(STATUS "******************************************************************************")
+
+# 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(extexample ${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(extexample
+        # 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 have commands to install your program.
 
-set(extension_target ${CMAKE_INSTALL_PREFIX}/lib/libextexample.so)
+if(UNIX)
+    # On Linux OS install into folder and symlink to UHD_MODULE_PATH
+    set(extension_target ${CMAKE_INSTALL_PREFIX}/lib/libextexample.so)
+    install(TARGETS extexample DESTINATION lib)
+    install(CODE "execute_process(COMMAND bash -c \"mkdir -p ${UHD_MODULE_PATH} && ln -s -f ${extension_target} -t ${UHD_MODULE_PATH}\")")
+else(UNIX)
+    # on other OS (Windows) install into UHD_MODULE_PATH
+    install(TARGETS extexample DESTINATION ${UHD_MODULE_PATH})
+endif(UNIX)
 
-install(TARGETS extexample DESTINATION lib)
-install(CODE "execute_process(COMMAND bash -c \"mkdir -p ${UHD_MODULE_PATH} && ln -s -f ${extension_target} -t ${UHD_MODULE_PATH}\")")