makes the core consumable as a CMake subproject

CMakeLists.txt

@@ -36,16 +36,22 @@ option(ENABLE_SHM_OUTPUT "Build shared-memory output support (requires ImageStre
 
 cmake_minimum_required(VERSION 3.12)
 
-find_program(GXX_COMPILER NAMES g++)
-
-if(GXX_COMPILER)
-    message(STATUS "Found g++: ${GXX_COMPILER}")
-    set(CMAKE_CXX_COMPILER ${GXX_COMPILER})
-else()
-    message(FATAL_ERROR "g++ compiler not found. Please install g++ and try again.")
+# Choosing the compiler belongs to whoever owns the build. A parent project has
+# already detected a compiler by the time it descends into this file, and
+# overriding that here would cause CMake to discard its cache and reconfigure,
+# losing the command line, -DCONTROLLER included
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    find_program(GXX_COMPILER NAMES g++)
+
+    if(GXX_COMPILER)
+        message(STATUS "Found g++: ${GXX_COMPILER}")
+        set(CMAKE_CXX_COMPILER ${GXX_COMPILER})
+    else()
+        message(FATAL_ERROR "g++ compiler not found. Please install g++ and try again.")
+    endif()
 endif()
 
-project(camera)
+project(camerad)
 
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -54,8 +60,9 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 set(PROJECT_BASE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 # A wheel build has nowhere to put a source-tree bin/, so let CMake keep its
-# outputs in the build directory
-if (NOT SKBUILD)
+# outputs in the build directory. A project that add_subdirectory()s this one
+# has nowhere to put them either, and its source tree is not ours to write into
+if (NOT SKBUILD AND CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BASE_DIR}/bin)
   set(LIBRARY_OUTPUT_PATH ${PROJECT_BASE_DIR}/lib)
 endif()

camerad/CMakeLists.txt

@@ -127,16 +127,32 @@ list (FILTER INSTRUMENT_SOURCES EXCLUDE REGEX "_interface_factory\\.cpp$")
 
 # ----------------------------------------------------------------------------
 # Camera Interface Base
+#
+# Controller-agnostic. Carries its own include directories and link interface
+# rather than relying on the directory-scoped include_directories above, which
+# a project consuming this one does not inherit
 # ----------------------------------------------------------------------------
-list (APPEND INTERFACE_SOURCES
+add_library(camerad_base
   ${CAMERAD_DIR}/camera_interface.cpp
   ${CAMERAD_DIR}/image_process.cpp
   )
-add_library(${INTERFACE_TARGET} ${INTERFACE_SOURCES})
-target_link_libraries(${INTERFACE_TARGET}
+target_include_directories(camerad_base PUBLIC
+                      ${CAMERAD_DIR}
+                      ${PROJECT_BASE_DIR}/common
+                      ${PROJECT_BASE_DIR}/utils
+                      )
+target_link_libraries(camerad_base PUBLIC
                       common
+                      logentry
                       frame_output_factory
                       )
+
+# ----------------------------------------------------------------------------
+# controller implementation, linking the base PUBLIC so that anything
+# depending on the controller gets the base transitively
+# ----------------------------------------------------------------------------
+add_library(${INTERFACE_TARGET} ${INTERFACE_SOURCES})
+target_link_libraries(${INTERFACE_TARGET} PUBLIC camerad_base)
 target_include_directories(${INTERFACE_TARGET} PUBLIC ${INTERFACE_INCLUDES})
 
 # ----------------------------------------------------------------------------

common/CMakeLists.txt

@@ -16,4 +16,4 @@ include_directories(${PROJECT_BASE_DIR}/utils)    # needed for logentry
 add_library(common STATIC
         ${PROJECT_UTILS_DIR}/common.cpp
 )
-target_link_libraries(common nlohmann_json::nlohmann_json)
+target_link_libraries(common nlohmann_json::nlohmann_json logentry)

utils/CMakeLists.txt

@@ -46,6 +46,7 @@ find_library(FITSWRITER_CCFITS_LIB CCfits NAMES libCCfits PATHS /usr/local/lib /
 find_library(FITSWRITER_CFITS_LIB cfitsio NAMES libcfitsio PATHS /usr/local/lib /opt/homebrew/lib)
 target_link_libraries(fits_writer
         nlohmann_json::nlohmann_json
+        utilities
         ${FITSWRITER_CCFITS_LIB}
         ${FITSWRITER_CFITS_LIB}
 )