[Teem-commit] SF.net SVN: teem:[7409] teem/trunk/CMake/FindFFTW3-v2 .cmake

[<kin...@us...>]

Revision: 7409
          http://sourceforge.net/p/teem/code/7409
Author:   kindlmann
Date:     2025-09-12 03:52:47 +0000 (Fri, 12 Sep 2025)
Log Message:
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future new version

Added Paths:
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    teem/trunk/CMake/FindFFTW3-v2.cmake

Added: teem/trunk/CMake/FindFFTW3-v2.cmake
===================================================================
--- teem/trunk/CMake/FindFFTW3-v2.cmake	                        (rev 0)
+++ teem/trunk/CMake/FindFFTW3-v2.cmake	2025-09-12 03:52:47 UTC (rev 7409)
@@ -0,0 +1,62 @@
+# CMake/FindFFTW3.cmake: Slightly better way of looking for FFTW3 package
+# Copyright (C) 2025  University of Chicago
+# See ../LICENSE.txt for licensing terms
+
+# Even though CMake already has a built-in FindFFTW3.cmake, it assumes that fftw3 was
+# installed locally via CMake, but that's not what e.g. (mac) brew or (linux) apt
+# actually does, so find_package(FFTW3) can succeed but is not able to define imported
+# targets for use with target_link_libraries(FFTW3::fftw3) This is a long-standing issue:
+# https://github.com/FFTW/fftw3/issues/130
+# and there must be various solutions out there, since ChatGPT basically wrote the code
+# below (and is characterically unable to provide a citation for similarly simple but
+# working code online)
+
+# TODO: handle the various variants for different precisions
+# See FindFFTW3-multiprec.cmake for inspiration
+
+# NOTE: If a working FFTW3Config.cmake is found, it will define
+# FFTW3::fftw3 for us already, so we don’t have to do anything else.
+# This fallback only runs when FFTW3_FOUND is still FALSE.
+if (NOT FFTW3_FOUND)
+
+  # Include the helper macro for standard handling of results
+  include(FindPackageHandleStandardArgs)
+
+  # Look for the FFTW3 header. Users can help by setting FFTW3_DIR or
+  # by making sure the header is somewhere in the default search paths.
+  find_path(FFTW3_INCLUDE_DIR
+    NAMES fftw3.h
+    HINTS ENV FFTW3_DIR  # WHAT MORE hints?
+    PATH_SUFFIXES include
+  )
+
+  # Look for the FFTW3 library. Allow FFTW3_DIR to point to its prefix.
+  find_library(FFTW3_LIBRARY
+    NAMES fftw3
+    HINTS ENV FFTW3_DIR  # WHAT MORE hints?
+    PATH_SUFFIXES lib
+  )
+
+  # Standard handling macro: sets FFTW3_FOUND if successful
+  find_package_handle_standard_args(FFTW3
+    REQUIRED_VARS FFTW3_LIBRARY FFTW3_INCLUDE_DIR
+  )
+
+  # If we did find FFTW3, but no imported target exists yet,
+  # create our own IMPORTED target so downstream code can use:
+  #     target_link_libraries(myprog PRIVATE FFTW3::fftw3)
+  if (FFTW3_FOUND AND NOT TARGET FFTW3::fftw3)
+    add_library(FFTW3::fftw3 UNKNOWN IMPORTED)
+    set_target_properties(FFTW3::fftw3 PROPERTIES
+      IMPORTED_LOCATION             "${FFTW3_LIBRARY}"
+      INTERFACE_INCLUDE_DIRECTORIES "${FFTW3_INCLUDE_DIR}"
+      # HEY no INTERFACE_LINK_LIBRARIES ?
+    )
+  endif()
+endif()
+
+if (FFTW3_FOUND)
+  message(STATUS "Using FFTW3: ${FFTW3_LIBRARY}")
+else()
+  message(STATUS "FFTW3 not found")
+endif()

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