4 files changed, 71 insertions, 1 deletions
diff --git a/gr-howto-write-a-block/CMakeLists.txt b/gr-howto-write-a-block/CMakeLists.txt
index 02b13c6b69..d5d04e24d0 100644
--- a/gr-howto-write-a-block/CMakeLists.txt
+++ b/gr-howto-write-a-block/CMakeLists.txt
@@ -94,6 +94,10 @@ if(NOT GNURADIO_CORE_FOUND)
     message(FATAL_ERROR "GnuRadio Core required to compile howto")
 endif()
 
+# Handle gr_log enable/disable
+include(GrMiscUtils) #define LIB_SUFFIX
+GR_LOGGING()
+
 ########################################################################
 # Setup the include and linker paths
 ########################################################################
@@ -101,12 +105,14 @@ include_directories(
     ${CMAKE_SOURCE_DIR}/include
     ${GNURADIO_CORE_INCLUDE_DIRS}
     ${GRUEL_INCLUDE_DIRS}
+    ${LOG4CXX_INCLUDE_DIRS}
     ${Boost_INCLUDE_DIRS}
 )
 
 link_directories(
     ${GNURADIO_CORE_LIBRARY_DIRS}
     ${GRUEL_LIBRARY_DIRS}
+    ${LOG4CXX_LIBRARY_DIRS}
     ${Boost_LIBRARY_DIRS}
 )
 
diff --git a/gr-howto-write-a-block/cmake/Modules/FindLog4cxx.cmake b/gr-howto-write-a-block/cmake/Modules/FindLog4cxx.cmake
new file mode 100644
index 0000000000..b1e4f6f1f7
--- /dev/null
+++ b/gr-howto-write-a-block/cmake/Modules/FindLog4cxx.cmake
@@ -0,0 +1,28 @@
+#   CMake module to find LOG4CXX library
+
+INCLUDE(FindPkgConfig)
+PKG_CHECK_MODULES(PC_LOG4CXX liblog4cxx)
+
+FIND_PATH(
+    LOG4CXX_INCLUDE_DIRS
+    NAMES log4cxx/log4cxx.h
+    HINTS $ENV{LOG4CXX_DIR}/include
+        ${PC_LOG4CXX_INCLUDE_DIRS}
+    PATHS /usr/local/include
+          /usr/include
+)
+
+FIND_LIBRARY(
+    LOG4CXX_LIBRARIES
+    NAMES log4cxx
+    HINTS $ENV{LOG4CXX_DIR}/lib
+        ${PC_LOG4CXX_LIBRARIES}
+    PATHS /usr/local/lib
+          /usr/local/lib64
+          /usr/lib
+          /usr/lib64
+)
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(LOG4CXX DEFAULT_MSG LOG4CXX_LIBRARIES LOG4CXX_INCLUDE_DIRS)
+MARK_AS_ADVANCED(LOG4CXX_LIBRARIES LOG4CXX_INCLUDE_DIRS)
diff --git a/gr-howto-write-a-block/cmake/Modules/GrMiscUtils.cmake b/gr-howto-write-a-block/cmake/Modules/GrMiscUtils.cmake
index 9331d5debc..cffe2f6540 100644
--- a/gr-howto-write-a-block/cmake/Modules/GrMiscUtils.cmake
+++ b/gr-howto-write-a-block/cmake/Modules/GrMiscUtils.cmake
@@ -208,3 +208,35 @@ function(GR_GEN_TARGET_DEPS name var)
         set(${var} "DEPENDS;${name};COMMAND;${name}" PARENT_SCOPE)
     endif()
 endfunction(GR_GEN_TARGET_DEPS)
+
+
+########################################################################
+# Control use of gr_log
+# Usage:
+#   GR_LOGGING()
+#
+# Will set ENABLE_GR_LOG to 1 by default.
+# Can manually set with -DENABLE_GR_LOG=0|1
+########################################################################
+function(GR_LOGGING)
+  find_package(Log4cxx)
+
+  OPTION(ENABLE_GR_LOG "Use gr_log" ON)
+  
+  if(NOT LOG4CXX_FOUND)
+    SET(ENABLE_GR_LOG OFF)
+  endif(NOT LOG4CXX_FOUND)
+
+  message(STATUS "ENABLE_GR_LOG set to ${ENABLE_GR_LOG}.")
+
+  if(ENABLE_GR_LOG)
+    add_definitions( -DENABLE_GR_LOG )
+  else(ENABLE_GR_LOG)
+    # If not enabled or available, set these variable to
+    # blank so we can use them later without having to
+    # check ENABLE_GR_LOG each time.
+    SET(LOG4CXX_INCLUDE_DIRS "" CACHE INTERNAL "" FORCE)
+    SET(LOG4CXX_LIBRARY_DIRS "" CACHE INTERNAL "" FORCE)
+    SET(LOG4CXX_LIBRARIES "" CACHE INTERNAL "" FORCE)
+  endif(ENABLE_GR_LOG)
+endfunction(GR_LOGGING)
diff --git a/gr-howto-write-a-block/lib/CMakeLists.txt b/gr-howto-write-a-block/lib/CMakeLists.txt
index 835ae02d60..a55bb1fa4a 100644
--- a/gr-howto-write-a-block/lib/CMakeLists.txt
+++ b/gr-howto-write-a-block/lib/CMakeLists.txt
@@ -23,7 +23,11 @@
 include(GrPlatform) #define LIB_SUFFIX
 
 add_library(gnuradio-howto SHARED howto_square_ff.cc howto_square2_ff.cc)
-target_link_libraries(gnuradio-howto ${Boost_LIBRARIES} ${GRUEL_LIBRARIES} ${GNURADIO_CORE_LIBRARIES})
+target_link_libraries(gnuradio-howto
+    ${Boost_LIBRARIES}
+    ${GRUEL_LIBRARIES}
+    ${GNURADIO_CORE_LIBRARIES}
+    ${LOG4CXX_LIBRARIES})
 set_target_properties(gnuradio-howto PROPERTIES DEFINE_SYMBOL "gnuradio_howto_EXPORTS")
 
 ########################################################################