[Teem-commit] SF.net SVN: teem:[7387] teem/trunk/CMake/CheckAirExis ts.cmake

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

Revision: 7387
          http://sourceforge.net/p/teem/code/7387
Author:   kindlmann
Date:     2025-09-10 01:20:21 +0000 (Wed, 10 Sep 2025)
Log Message:
-----------
Now that we have CheckLibM.cmake in its own file, this also belows in its own file

Added Paths:
-----------
    teem/trunk/CMake/CheckAirExists.cmake

Added: teem/trunk/CMake/CheckAirExists.cmake
===================================================================
--- teem/trunk/CMake/CheckAirExists.cmake	                        (rev 0)
+++ teem/trunk/CMake/CheckAirExists.cmake	2025-09-10 01:20:21 UTC (rev 7387)
@@ -0,0 +1,100 @@
+# CMake/CheckAirExists.cmake: see if AIR_EXISTS() macro works like isfinite()
+# Copyright (C) 2025  University of Chicago
+# See ../LICENSE.txt for licensing terms
+
+# A lot of work for one little macro (which GLK started using before the functionally
+# equivalent isfinite() became widely available).  The little CMake/TestAIR_EXISTS.c
+# program tests the equivalent of AIR_EXISTS (but without directly using air.h's
+# AIR_EXISTS because this has to be stand-alone), to see if it can correctly detect
+# IEEE754 special values (NaNs and infinities). For this to be a useful test that informs
+# how the rest of Teem code will work, TestAIR_EXISTS.c needs to be compiled the same as
+# Teem itself will be compiled later.  Sadly, it was not until Teem V2 that this
+# consistency was actually enforced (!)  To further help debugging, we also print out
+# exactly how TestAIR_EXISTS.c is compiled, and we use try_compile instead of try_run
+# so the resulting executable file stays available for later inspection.
+#
+# (rejected but interesting debugging strategies:
+#  message(STATUS "Pausing CMake so you can inspect temporary files...")
+#  execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 30)
+#  or
+#  execute_process(COMMAND /bin/sh -c "read -p 'Press ENTER to continue...'")
+# )
+
+# "taex" = Test Air_EXists
+set(_taex_src "${CMAKE_CURRENT_LIST_DIR}/TestAIR_EXISTS.c")
+
+# Build flags for the probe (same as Teem itself)
+string(TOUPPER "${CMAKE_BUILD_TYPE}" _taex_BTUC)
+set(_taex_flags "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${_taex_BTUC}}")
+set(_taex_me "AIR_EXISTS (compiled \"${_taex_flags}\")")
+
+# Where we want a durable copy of the compiled probe
+if(WIN32)
+  set(_taex_copy "${CMAKE_BINARY_DIR}/TestAIR_EXISTS.exe")
+else()
+  set(_taex_copy "${CMAKE_BINARY_DIR}/TestAIR_EXISTS")
+endif()
+
+# Remove any stale copy from previous runs
+if(EXISTS "${_taex_copy}")
+  file(REMOVE "${_taex_copy}")
+endif()
+
+# Compile the probe
+message(CHECK_START "Testing whether macro ${_taex_me} detects IEEE754 special values")
+try_compile(
+  _taex_compiles         # boolean result: TRUE if compile succeeded
+  SOURCES "${_taex_src}" # one or more source files for the test
+  CMAKE_FLAGS
+    "-DCMAKE_VERBOSE_MAKEFILE=ON"
+    "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}"
+    "-DCMAKE_C_FLAGS_${_taex_BTUC}=${_taex_flags}"
+    "-DCMAKE_DEPENDS_USE_COMPILER=FALSE"  # no -MD/-MT/-MF dependency cruft
+  COPY_FILE "${_taex_copy}"     # copy the built executable to a stable path
+  OUTPUT_VARIABLE _taex_compile_out
+  COPY_FILE_ERROR _taex_copy_error
+)
+# Always show the captured compile output, as progress indication
+string(REPLACE "\n" "\n     " _taex_compile_out_indented "${_taex_compile_out}")
+message(STATUS "Compile output:\n     ${_taex_compile_out_indented}")
+
+if(NOT _taex_compiles)
+  message(CHECK_FAIL "compile failed")
+  message(FATAL_ERROR "Could not compile ${_taex_src}")
+elseif(_taex_copy_error)
+  message(CHECK_FAIL "copy failed")
+  message(FATAL_ERROR "Test program compiled but could not copy: ${_taex_copy_error}")
+elseif(NOT EXISTS "${_taex_copy}")
+  message(CHECK_FAIL "missing executable")
+  message(FATAL_ERROR "Test program compiled but file not found at ${_taex_copy}")
+else()
+  message(CHECK_PASS "compiled successfully")
+endif()
+
+# Run the test program
+message(CHECK_START "Running ${_taex_me} test program")
+# https://cmake.org/cmake/help/latest/command/execute_process.html
+execute_process(
+  COMMAND "${_taex_copy}"
+  RESULT_VARIABLE _taex_run_status
+  OUTPUT_VARIABLE _taex_run_out
+  ERROR_VARIABLE _taex_run_err
+)
+
+# Act on the results; set AIR_EXISTS_MACRO_FAILS
+if(_taex_run_status EQUAL 0)
+  message(CHECK_PASS "Yes, it detects IEEE754 special values")
+  set(AIR_EXISTS_MACRO_FAILS 0 CACHE INTERNAL "AIR_EXISTS macro works correctly")
+else()
+    # Always show stdout/stderr from the probe as indented sub-log
+  if(_taex_run_out)
+    string(REPLACE "\n" "\n     " _taex_run_out_indented "${_taex_run_out}")
+    message(STATUS "Probe stdout:\n     ${_taex_run_out_indented}")
+  endif()
+  if(_taex_run_err)
+    string(REPLACE "\n" "\n     " _taex_run_err_indented "${_taex_run_err}")
+    message(STATUS "Probe stderr:\n     ${_taex_run_err_indented}")
+  endif()
+  message(CHECK_FAIL "NO, it FAILS to detect IEEE754 special values")
+  set(AIR_EXISTS_MACRO_FAILS 1 CACHE INTERNAL "AIR_EXISTS macro fails")
+endif()

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