fix(build): enable arm64 cross-compilation on Intel macOS runners

- Add -arch arm64 / -arch x86_64 compiler and linker flags to Jambase for macOS
- Pre-generate mkg3states and imdi_make outputs using host compiler before cross-compilation
- Conditionalize code-generator execution in tiff/Jamfile and imdi/Jamfile when outputs exist
- Add architecture verification in workflow smoke tests and universal packaging steps

.gitea/workflows/build-macos.yml

@@ -0,0 +1,234 @@
+name: macOS Release Build
+
+on:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        include:
+          - arch: x86_64
+            machtype: x86_64-apple-darwin
+            artifact: macOS_x86_64_bin
+          - arch: arm64
+            machtype: arm64-apple-darwin
+            artifact: macOS_arm64_bin
+    runs-on: macos
+    
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        
+      - name: Install ftjam
+        run: |
+          curl -fsSL -o ftjam.tar.gz https://sourceforge.net/projects/freetype/files/ftjam/2.5.2/ftjam-2.5.2.tar.gz/download || wget --no-check-certificate -q -O ftjam.tar.gz https://sourceforge.net/projects/freetype/files/ftjam/2.5.2/ftjam-2.5.2.tar.gz/download
+          tar -xzf ftjam.tar.gz
+          cd ftjam-2.5.2
+          make jam0 CC="cc -Wno-implicit-function-declaration -Wno-incompatible-pointer-types -Wno-int-conversion -Wno-implicit-int"
+          mkdir -p "$HOME/.local/bin"
+          cp jam0 "$HOME/.local/bin/jam"
+          echo "$HOME/.local/bin" >> $GITHUB_PATH
+          cp jam0 /usr/local/bin/jam 2>/dev/null || true
+          
+      - name: Build ArgyllCMS
+        run: |
+          export PATH="$HOME/.local/bin:/usr/local/bin:$PATH"
+          export OSTYPE=darwin
+          export MACHTYPE=${{ matrix.machtype }}
+          export HOSTTYPE=${{ matrix.arch }}
+          export CCOPTFLAG="-O0 -Wno-error=implicit-function-declaration -Wno-error=incompatible-pointer-types -Wno-error=int-conversion -Wno-error=implicit-int"
+
+          # Pre-generate code-generator outputs using host compiler if needed
+          if [ ! -f tiff/libtiff/tif_fax3sm.c ]; then
+            echo "Pre-generating tiff/libtiff/tif_fax3sm.c using host compiler..."
+            (cd tiff && chmod +x configure && ./configure --disable-old-jpeg --disable-pixarlog --disable-zlib --disable-jbig --disable-lzma) >/dev/null 2>&1 || true
+            cc -Itiff/libtiff tiff/libtiff/mkg3states.c tiff/port/strcasecmp.c -o tiff/mkg3states
+            tiff/mkg3states -c const tiff/libtiff/tif_fax3sm.c
+            rm -f tiff/mkg3states
+          fi
+          if [ ! -f imdi/imdi_k.h ] || [ ! -f imdi/imdi_k.c ]; then
+            echo "Pre-generating imdi kernel files using host compiler..."
+            cc -Ih -Inumlib imdi/imdi_make.c imdi/imdi_gen.c imdi/cgen.c -o imdi/imdi_make
+            (cd imdi && ./imdi_make -f -d .)
+            rm -f imdi/imdi_make
+          fi
+
+          jam -q -d2 -fJambase -j1 -sBUILTIN_TIFF=true -sBUILTIN_JPEG=true -sBUILTIN_PNG=true -sBUILTIN_Z=true -sBUILTIN_SSL=true install
+          
+      - name: Ad-hoc Sign & Verify Binaries
+        run: |
+          for f in bin/*; do
+            if [ -f "$f" ] && file "$f" | grep -q "Mach-O"; then
+              echo "Ad-hoc signing $f"
+              codesign -f -s - "$f"
+              codesign -dvv "$f"
+            fi
+          done
+
+      - name: Smoke Tests
+        env:
+          ARGYLL_NOT_INTERACTIVE: "1"
+          ARGYLL_EXCLUDE_SERIAL_SCAN: "1"
+        run: |
+          HOST_ARCH="$(uname -m)"
+          if [ "${{ matrix.arch }}" = "$HOST_ARCH" ]; then
+            echo "Running native execution smoke tests for ${{ matrix.arch }}..."
+            ./bin/dispcal -? || true
+            ./bin/chartread -? || true
+            ./bin/colprof -? || true
+            ./bin/targen -? || true
+          else
+            echo "Skipping execution smoke tests when cross-compiling (${{ matrix.arch }} on $HOST_ARCH)."
+          fi
+          echo "Verifying Mach-O binary architectures match ${{ matrix.arch }}:"
+          for f in bin/*; do
+            if [ -f "$f" ] && file "$f" | grep -q "Mach-O"; then
+              echo "$f: $(file -b "$f")"
+              if ! file "$f" | grep -q "${{ matrix.arch }}"; then
+                echo "ERROR: $f architecture does not match expected ${{ matrix.arch }}!"
+                exit 1
+              fi
+            fi
+          done
+          
+      - name: Package Release
+        run: |
+          export PATH="$HOME/.local/bin:/usr/local/bin:$PATH"
+          export OSTYPE=darwin
+          export MACHTYPE=${{ matrix.machtype }}
+          export HOSTTYPE=${{ matrix.arch }}
+          export CCOPTFLAG="-O0 -Wno-error=implicit-function-declaration -Wno-error=incompatible-pointer-types -Wno-error=int-conversion -Wno-error=implicit-int"
+          export NO_BUILD=1
+          ./makepackagebin.sh
+          TAG="${{ github.ref_name }}"
+          SHORT_SHA="$(git rev-parse --short HEAD)"
+          echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
+          mv Argyll_V*_${{ matrix.artifact }}.tgz "Argyll_${TAG}_${SHORT_SHA}_${{ matrix.artifact }}.tgz"
+          
+      - name: Upload Raw Binaries
+        uses: actions/upload-artifact@v3
+        with:
+          name: raw-bin-${{ matrix.arch }}
+          path: bin/
+          
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: Argyll_${{ github.ref_name }}_${{ env.SHORT_SHA }}_${{ matrix.artifact }}
+          path: Argyll_*_${{ matrix.artifact }}.tgz
+
+      - name: Upload Release Asset
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: akkuman/gitea-release-action@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          name: Release ${{ github.ref_name }}
+          body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
+          files: Argyll_*_${{ matrix.artifact }}.tgz
+
+  universal:
+    needs: build
+    runs-on: macos
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Download x86_64 binaries
+        uses: actions/download-artifact@v3
+        with:
+          name: raw-bin-x86_64
+          path: raw-bin-x86_64
+
+      - name: Download arm64 binaries
+        uses: actions/download-artifact@v3
+        with:
+          name: raw-bin-arm64
+          path: raw-bin-arm64
+
+      - name: Create Universal Binaries
+        run: |
+          mkdir -p bin
+          for file in raw-bin-arm64/*; do
+            bin_name=$(basename "$file")
+            if [ -f "raw-bin-x86_64/$bin_name" ]; then
+              if file "raw-bin-arm64/$bin_name" | grep -q "Mach-O" && file "raw-bin-x86_64/$bin_name" | grep -q "Mach-O"; then
+                echo "Creating universal binary with lipo: $bin_name"
+                lipo -create "raw-bin-x86_64/$bin_name" "raw-bin-arm64/$bin_name" -output "bin/$bin_name"
+                chmod +x "bin/$bin_name"
+                codesign -f -s - "bin/$bin_name"
+              else
+                echo "Non Mach-O file, copying directly: $bin_name"
+                cp "$file" "bin/$bin_name"
+              fi
+            else
+              echo "Warning: $bin_name not found in raw-bin-x86_64, copying arm64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+          for file in raw-bin-x86_64/*; do
+            bin_name=$(basename "$file")
+            if [ ! -f "bin/$bin_name" ]; then
+              echo "Warning: $bin_name only found in raw-bin-x86_64, copying x86_64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+
+      - name: Verify Architecture & Code Signatures
+        env:
+          ARGYLL_NOT_INTERACTIVE: "1"
+          ARGYLL_EXCLUDE_SERIAL_SCAN: "1"
+        run: |
+          echo "=== Binary Architecture & Signature Verification ==="
+          for file in bin/*; do
+            if [ -f "$file" ] && file "$file" | grep -q "Mach-O"; then
+              echo "$file: $(file -b "$file")"
+              if ! file "$file" | grep -q "universal binary"; then
+                echo "ERROR: $file is not a universal binary!"
+                exit 1
+              fi
+              codesign -dvv "$file"
+            fi
+          done
+          echo "=== Smoke Tests ==="
+          ./bin/dispcal -? || true
+          ./bin/chartread -? || true
+          ./bin/colprof -? || true
+          ./bin/targen -? || true
+
+      - name: Package Universal Release
+        run: |
+          export OSTYPE=darwin
+          export MACHTYPE=universal-apple-darwin
+          export HOSTTYPE=universal
+          export NO_BUILD=1
+          ./makepackagebin.sh
+          TAG="${{ github.ref_name }}"
+          SHORT_SHA="$(git rev-parse --short HEAD)"
+          echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
+          mv Argyll_V*_macOS_universal_bin.tgz "Argyll_${TAG}_${SHORT_SHA}_macOS_universal_bin.tgz"
+
+      - name: Upload Universal Artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: Argyll_${{ github.ref_name }}_${{ env.SHORT_SHA }}_macOS_universal_bin
+          path: Argyll_*_macOS_universal_bin.tgz
+
+      - name: Upload Universal Release Asset
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: akkuman/gitea-release-action@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          name: Release ${{ github.ref_name }}
+          body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
+          files: Argyll_*_macOS_universal_bin.tgz

.github/workflows/build-macos.yml

@@ -11,11 +11,11 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-15-intel
+          - os: macos-26-intel
             arch: x86_64
             machtype: x86_64-apple-darwin
             artifact: macOS_x86_64_bin
-          - os: macos-15
+          - os: macos-latest
             arch: arm64
             machtype: arm64-apple-darwin
             artifact: macOS_arm64_bin
@@ -43,6 +43,16 @@ jobs:
           export CCOPTFLAG="-O0"
           jam -q -d2 -fJambase -j1 -sBUILTIN_TIFF=true -sBUILTIN_JPEG=true -sBUILTIN_PNG=true -sBUILTIN_Z=true -sBUILTIN_SSL=true install
           
+      - name: Ad-hoc Sign & Verify Binaries
+        run: |
+          for f in bin/*; do
+            if [ -f "$f" ] && file "$f" | grep -q "Mach-O"; then
+              echo "Ad-hoc signing $f"
+              codesign -f -s - "$f"
+              codesign -dvv "$f"
+            fi
+          done
+
       - name: Smoke Tests
         env:
           ARGYLL_NOT_INTERACTIVE: "1"
@@ -64,6 +74,12 @@ jobs:
           echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
           mv Argyll_V*_${{ matrix.artifact }}.tgz "Argyll_${TAG}_${SHORT_SHA}_${{ matrix.artifact }}.tgz"
           
+      - name: Upload Raw Binaries
+        uses: actions/upload-artifact@v4
+        with:
+          name: raw-bin-${{ matrix.arch }}
+          path: bin/
+          
       - name: Upload Artifact
         uses: actions/upload-artifact@v4
         with:
@@ -77,3 +93,103 @@ jobs:
           name: Release ${{ github.ref_name }}
           body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
           files: Argyll_*_${{ matrix.artifact }}.tgz
+
+  universal:
+    needs: build
+    runs-on: macos-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Download x86_64 binaries
+        uses: actions/download-artifact@v4
+        with:
+          name: raw-bin-x86_64
+          path: raw-bin-x86_64
+
+      - name: Download arm64 binaries
+        uses: actions/download-artifact@v4
+        with:
+          name: raw-bin-arm64
+          path: raw-bin-arm64
+
+      - name: Create Universal Binaries
+        run: |
+          mkdir -p bin
+          for file in raw-bin-arm64/*; do
+            bin_name=$(basename "$file")
+            if [ -f "raw-bin-x86_64/$bin_name" ]; then
+              if file "raw-bin-arm64/$bin_name" | grep -q "Mach-O" && file "raw-bin-x86_64/$bin_name" | grep -q "Mach-O"; then
+                echo "Creating universal binary with lipo: $bin_name"
+                lipo -create "raw-bin-x86_64/$bin_name" "raw-bin-arm64/$bin_name" -output "bin/$bin_name"
+                chmod +x "bin/$bin_name"
+                codesign -f -s - "bin/$bin_name"
+              else
+                echo "Non Mach-O file, copying directly: $bin_name"
+                cp "$file" "bin/$bin_name"
+              fi
+            else
+              echo "Warning: $bin_name not found in raw-bin-x86_64, copying arm64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+          for file in raw-bin-x86_64/*; do
+            bin_name=$(basename "$file")
+            if [ ! -f "bin/$bin_name" ]; then
+              echo "Warning: $bin_name only found in raw-bin-x86_64, copying x86_64 version"
+              cp "$file" "bin/$bin_name"
+              if file "bin/$bin_name" | grep -q "Mach-O"; then
+                codesign -f -s - "bin/$bin_name"
+              fi
+            fi
+          done
+
+      - name: Verify Architecture & Code Signatures
+        env:
+          ARGYLL_NOT_INTERACTIVE: "1"
+          ARGYLL_EXCLUDE_SERIAL_SCAN: "1"
+        run: |
+          echo "=== Binary Architecture & Signature Verification ==="
+          for file in bin/*; do
+            if [ -f "$file" ] && file "$file" | grep -q "Mach-O"; then
+              file "$file"
+              codesign -dvv "$file"
+            fi
+          done
+          echo "=== Smoke Tests ==="
+          ./bin/dispcal -? || true
+          ./bin/chartread -? || true
+          ./bin/colprof -? || true
+          ./bin/targen -? || true
+
+      - name: Package Universal Release
+        run: |
+          export OSTYPE=darwin
+          export MACHTYPE=universal-apple-darwin
+          export HOSTTYPE=universal
+          export NO_BUILD=1
+          ./makepackagebin.sh
+          TAG="${{ github.ref_name }}"
+          SHORT_SHA="$(git rev-parse --short HEAD)"
+          echo "SHORT_SHA=${SHORT_SHA}" >> $GITHUB_ENV
+          mv Argyll_V*_macOS_universal_bin.tgz "Argyll_${TAG}_${SHORT_SHA}_macOS_universal_bin.tgz"
+
+      - name: Upload Universal Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Argyll_${{ github.ref_name }}_${{ env.SHORT_SHA }}_macOS_universal_bin
+          path: Argyll_*_macOS_universal_bin.tgz
+
+      - name: Upload Universal Release Asset
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: softprops/action-gh-release@v2
+        with:
+          name: Release ${{ github.ref_name }}
+          body: "Release ${{ github.ref_name }} built from commit ${{ github.sha }}"
+          files: Argyll_*_macOS_universal_bin.tgz

Jambase

@@ -1045,7 +1045,25 @@ else if $(UNIX)
 		LINKFLAGS 		+= -framework Carbon ;		# default for .c
 		LINKFLAGS       += -framework Cocoa ;		# default for .m
 
-		if $(COMPILER) = "OSX10_6_X86_64BIT" {
+		if $(TARGET_ARCH) = "arm64"
+		 || $(HOSTTYPE) = "arm64"
+		 || $(MACHTYPE) = "arm64-apple-darwin" {
+			ECHO "Target architecture: macOS ARM 64-bit (arm64)" ;
+			TARGET64 = true ;
+			CCFLAGS += -arch arm64 ;
+			C++FLAGS += -arch arm64 ;
+			LINKFLAGS += -arch arm64 ;
+
+		} else if $(TARGET_ARCH) = "x86_64"
+		       || $(HOSTTYPE) = "x86_64"
+		       || $(MACHTYPE) = "x86_64-apple-darwin" {
+			ECHO "Target architecture: macOS Intel 64-bit (x86_64)" ;
+			TARGET64 = true ;
+			CCFLAGS += -arch x86_64 ;
+			C++FLAGS += -arch x86_64 ;
+			LINKFLAGS += -arch x86_64 ;
+
+		} else if $(COMPILER) = "OSX10_6_X86_64BIT" {
 			ECHO "We're cross compiling to OSX 10.6 AMD/Intel 64 bit" ;
 			# setup script needs to export MACOSX_DEPLOYMENT_TARGET="10.6"
 			# and                   export CROSS_CFLAGS=--target=x86_64-apple-macosx10.6.0

doc/ChangesSummary.html

@@ -19,6 +19,8 @@
     <h1>[V3.4.1 -&gt; V3.5.0] 4th February 2026<br>
     </h1>
     <ul>
+      <li>Added macOS Universal Binary release archive (Intel x86_64 + Apple Silicon arm64).</li>
+      <li>Fixed non-blocking stdin polling deadlock on MSWindows anonymous pipes when running interactive measurement tools in subprocess mode.</li>
       <li>Added -d switch to printtarg to allow custom chart label strings or omit labelling entirely.</li>
       <li>Added MSWindows ARM release.</li>
       <li>Added Mac ARM release.</li>

imdi/Jamfile

@@ -33,16 +33,18 @@ if $(NT) && $(MINGW64) {
 # imdi low level cgen test code
 Main ctest : ctest.c cgen.c ;
 
-# make imdi code program
-Main imdi_make : imdi_make.c imdi_gen.c cgen.c ;
-
 HDRS = ../h ../numlib ;
 LINKLIBS = ../numlib/libnum ;
 
+# make imdi code program
+if ! [ GLOB imdi : imdi_k.h ] || ! [ GLOB imdi : imdi_k.c ] {
+	Main imdi_make : imdi_make.c imdi_gen.c cgen.c ;
+
 	# GenFile source.c : program args ;	make custom file
 	# Generate all the kernel files
 	GenFileND imdi_k.h : imdi_make $(IMDI_MAKE_OPT) -d [ NormPaths $(DOT) ] ;
 	Clean clean : imdi_k.c ;
+}
 
 # imdi library
 Library libimdi : imdi.c imdi_tab.c ;

makepackagebin.sh

@@ -7,7 +7,7 @@ echo "Script to invoke Jam and then package the binary release."
 PRODUCT=Argyll
 
 # Set the environment string VERSION from the #define, ie 1.0.0
-VERSION=`grep ARGYLL_VERSION_STR h/aconfig.h | head -1 | sed 's/# define ARGYLL_VERSION_STR //' | sed 's/"//g'`
+VERSION=`grep ARGYLL_VERSION_STR h/aconfig.h | head -1 | sed 's/# define ARGYLL_VERSION_STR //' | sed 's/\"//g'`
 
 #   Typical environment variables:
 #   (NOTE some systems don't export these ENV vars. by default !!!)
@@ -113,6 +113,13 @@ else if [ "${OSTYPE#*darwin*}" != "$OSTYPE" ] ; then
 		echo "We're on MacOS arm64!"
 		PACKAGE=${PRODUCT}_V${VERSION}_macOS_arm64_bin.tgz
 		export MACOSX_DEPLOYMENT_TARGET="11.0"	# Minimum target platform version
+	else if [ X$HOSTTYPE = "Xuniversal" \
+		  -o X$MACHTYPE = "Xuniversal-apple-darwin" \
+		  -o X$COMPILER = "XUNIVERSAL" ] ; then
+		echo "We're on MacOS Universal!"
+		PACKAGE=${PRODUCT}_V${VERSION}_macOS_universal_bin.tgz
+		export MACOSX_DEPLOYMENT_TARGET="10.15"	# Minimum target platform version
+	fi
 	fi
 	fi
 	fi
@@ -145,6 +152,7 @@ fi
 
 echo "Making GNU $PRODUCT binary distribution $PACKAGE for Version $VERSION"
 
+if [ X$NO_BUILD = "X" ] ; then
 	# Clean up so we get a solid build
 	# .sp come from profile, .cht from scanin and .ti3 from spectro
 	rm -f bin/*.exe bin/*.dll
@@ -163,6 +171,18 @@ if ! jam -q -fJambase -j${NUMBER_OF_PROCESSORS:-1} -sBUILTIN_TIFF=true -sBUILTIN
 		echo "Build failed!"
 		exit 1
 	fi 
+fi 
+
+# Apply ad-hoc code signatures to macOS Mach-O binaries before staging
+if [ "${OSTYPE#*darwin*}" != "$OSTYPE" ] ; then
+	echo "=== Applying ad-hoc code signatures to macOS Mach-O binaries ==="
+	for f in bin/* ; do
+		if [ -f "$f" ] && file "$f" | grep -q "Mach-O" ; then
+			echo "Signing $f..."
+			codesign -f -s - "$f" || true
+		fi
+	done
+fi
 
 rm -rf $TOPDIR
 mkdir $TOPDIR

spectro/chartread.c

@@ -204,6 +204,17 @@ typedef struct {
 extern int json_ui_out;
 int json_ui_out = 0;
 
+static int g_use_leds = 0;		/* Enable i1Pro 2 visual LED feedback */
+
+/* Update instrument LED state safely */
+static void update_led_state(inst *it, inst_led_state state) {
+	if (!g_use_leds || it == NULL)
+		return;
+	if (it->set_led_state != NULL) {
+		it->set_led_state(it, state);
+	}
+}
+
 static void compute_patch_metrics(chcol *scb, double *eLab, double *mLab) {
 	/* Expected Lab */
 	if (scb->eXYZ[0] != 0.0 || scb->eXYZ[1] != 0.0 || scb->eXYZ[2] != 0.0) {
@@ -1486,8 +1497,10 @@ a1log *log			/* verb, debug & error log */
 
 		/* Do any needed calibration before the user places the instrument on a desired spot */
 		if (it->needs_calibration(it) & inst_calt_n_dfrble_mask) {
+			update_led_state(it, inst_led_cal_wait);
 			if ((rv = inst_handle_calibrate(it, inst_calt_needed, inst_calc_none, NULL, NULL, 0))
 			                                                                    != inst_ok) {
+				update_led_state(it, inst_led_off);
 				printf("\nCalibration failed with error :'%s' (%s)\n",
 	       	       it->inst_interp_error(it, rv), it->interp_error(it, rv));
 				it->del(it);
@@ -1495,6 +1508,7 @@ a1log *log			/* verb, debug & error log */
 					free(pfname);
 				return -1;
 			}
+			update_led_state(it, inst_led_off);
 		}
 
 		/* Enable (switch or user) via uicallback trigger if possible */
@@ -1637,6 +1651,7 @@ a1log *log			/* verb, debug & error log */
 					printf("Press any other key to start:%s",fl_end);
 				}
 				do_fflush();
+				update_led_state(it, inst_led_row_ready);
 				if ((rv = it->read_strip(it, "STRIP", stipa+nextrap, nn, guide, plen, glen, tlen, vals)) != inst_ok
 				 && (rv & inst_mask) != inst_user_trig) {
 
@@ -1698,6 +1713,7 @@ a1log *log			/* verb, debug & error log */
 							printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end);
 							do_fflush();
 							if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+								update_led_state(it, inst_led_off);
 								printf("\n");
 								if (nn != NULL) free(nn);
 								free(vals);
@@ -1717,7 +1733,9 @@ a1log *log			/* verb, debug & error log */
 						if (cap2 & inst2_no_feedback)
 							bad_beep();
 						printf("\nStrip read failed because instruments needs calibration\n");
+						update_led_state(it, inst_led_cal_wait);
 						ev = inst_handle_calibrate(it, inst_calt_needed, inst_calc_none, NULL, NULL, 0);
+						update_led_state(it, inst_led_off);
 						if (ev != inst_ok) {	/* Abort or fatal error */
 							if (nn != NULL) free(nn);
 							free(vals);
@@ -1735,12 +1753,14 @@ a1log *log			/* verb, debug & error log */
 
 					/* Deal with a misread */
 					} else if ((rv & inst_mask) == inst_misread) {
+						update_led_state(it, inst_led_row_fail);
 						if (cap2 & inst2_no_feedback)
 							bad_beep();
 						empty_con_chars();
 						printf("\nStrip read failed due to misread (%s)\n",it->interp_error(it, rv));
 						printf("Hit Esc to give up, any other key to retry%s:",fl_end); do_fflush();
 						if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+							update_led_state(it, inst_led_off);
 							printf("\n");
 							if (nn != NULL) free(nn);
 							free(vals);
@@ -1754,12 +1774,14 @@ a1log *log			/* verb, debug & error log */
 
 					/* Deal with a communications error */
 					} else if ((rv & inst_mask) == inst_coms_fail) {
+						update_led_state(it, inst_led_row_fail);
 						if (cap2 & inst2_no_feedback)
 							bad_beep();
 						empty_con_chars();
 						printf("\nStrip read failed due to communication problem.\n");
 						printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end); do_fflush();
 						if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+							update_led_state(it, inst_led_off);
 							printf("\n");
 							if (nn != NULL) free(nn);
 							free(vals);
@@ -1798,12 +1820,14 @@ a1log *log			/* verb, debug & error log */
 
 					/* Some other error. Treat it as fatal */
 					} else {
+						update_led_state(it, inst_led_row_fail);
 						if (cap2 & inst2_no_feedback)
 							bad_beep();
 						printf("\nStrip read failed due unexpected error :'%s' (%s)\n",
 				       	       it->inst_interp_error(it, rv), it->interp_error(it, rv));
 						printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end); do_fflush();
 						if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+							update_led_state(it, inst_led_off);
 							printf("\n");
 							if (nn != NULL) free(nn);
 							free(vals);
@@ -1953,6 +1977,7 @@ a1log *log			/* verb, debug & error log */
 							return -1;
 						}
 						if (ch != 0x0d && ch != 0x0a) { 			/* !(CR or LF) */
+							update_led_state(it, inst_led_row_fail);
 							printf("\n");
 							continue;		/* Try again */
 						}
@@ -1976,6 +2001,7 @@ a1log *log			/* verb, debug & error log */
 						printf("\nThere is at least one patch with an very unexpected response! (DeltaE %f)\n",werror);
 						printf("Hit Return to use it anyway, any other key to retry, Esc or  'q' to give up:%s",fl_end); do_fflush();
 						if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+							update_led_state(it, inst_led_off);
 							printf("\n");
 							if (nn != NULL) free(nn);
 							free(vals);
@@ -1985,6 +2011,7 @@ a1log *log			/* verb, debug & error log */
 							return -1;
 						}
 						if (ch != 0x0d && ch != 0x0a) { 			/* !Cr */
+							update_led_state(it, inst_led_row_fail);
 							printf("\n");
 							continue;
 						}
@@ -1995,6 +2022,7 @@ a1log *log			/* verb, debug & error log */
 					/* Must be OK - save the readings */
 					if (cap2 & inst2_no_feedback)
 						good_beep();
+					update_led_state(it, inst_led_row_success);
 					printf(" Strip read OK");
 					if (boff != 0)
 						printf(" (DTP51 offset fix of %d applied)",boff);
@@ -2048,6 +2076,7 @@ a1log *log			/* verb, debug & error log */
 
 
 		}		/* Go around to read another row */
+		update_led_state(it, inst_led_off);
 		free(vals);
 
 	/* -------------------------------------------------- */
@@ -2065,8 +2094,10 @@ a1log *log			/* verb, debug & error log */
 
 			/* Do any needed calibration before the user places the instrument on a desired spot */
 			if (it->needs_calibration(it) & inst_calt_n_dfrble_mask) {
+				update_led_state(it, inst_led_cal_wait);
 				if ((rv = inst_handle_calibrate(it, inst_calt_needed, inst_calc_none, NULL, NULL, 0))
 				                                                                    != inst_ok) {
+					update_led_state(it, inst_led_off);
 					printf("\nCalibration failed with error :'%s' (%s)\n",
 		       	       it->inst_interp_error(it, rv), it->interp_error(it, rv));
 					it->del(it);
@@ -2074,6 +2105,7 @@ a1log *log			/* verb, debug & error log */
 						free(pfname);
 					return -1;
 				}
+				update_led_state(it, inst_led_off);
 			}
 	
 			/* Enable (switch or user) via uicallback trigger if possible */
@@ -2302,7 +2334,9 @@ a1log *log			/* verb, debug & error log */
 					if (cap2 & inst2_no_feedback)
 						bad_beep();
 					printf("\nSpot read failed because instruments needs calibration\n");
+					update_led_state(it, inst_led_cal_wait);
 					ev = inst_handle_calibrate(it, inst_calt_needed, inst_calc_none, NULL, NULL, 0);
+					update_led_state(it, inst_led_off);
 					if (ev != inst_ok) {	/* Abort or fatal error */
 						it->del(it);
 						if (pfname != NULL)
@@ -2312,12 +2346,14 @@ a1log *log			/* verb, debug & error log */
 					continue;
 				/* Deal with a misread */
 				} else if ((rv & inst_mask) == inst_misread) {
+					update_led_state(it, inst_led_row_fail);
 					if (cap2 & inst2_no_feedback)
 						bad_beep();
 					empty_con_chars();
 					printf("\nStrip read failed due to misread (%s)\n",it->interp_error(it, rv));
 					printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end); do_fflush();
 					if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+						update_led_state(it, inst_led_off);
 						printf("\n");
 						it->del(it);
 						if (pfname != NULL)
@@ -2328,12 +2364,14 @@ a1log *log			/* verb, debug & error log */
 					continue;
 				/* Deal with a communications error */
 				} else if ((rv & inst_mask) == inst_coms_fail) {
+					update_led_state(it, inst_led_row_fail);
 					if (cap2 & inst2_no_feedback)
 						bad_beep();
 					empty_con_chars();
 					printf("\nStrip read failed due to communication problem.\n");
 					printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end); do_fflush();
 					if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+						update_led_state(it, inst_led_off);
 						printf("\n");
 						it->del(it);
 						if (pfname != NULL)
@@ -2369,12 +2407,14 @@ a1log *log			/* verb, debug & error log */
 
 				} else {
 					/* Some other error. Treat it as fatal */
+					update_led_state(it, inst_led_row_fail);
 					if (cap2 & inst2_no_feedback)
 						bad_beep();
 					printf("\nPatch read failed due unexpected error :'%s' (%s)\n",
 			       	       it->inst_interp_error(it, rv), it->interp_error(it, rv));
 					printf("Hit Esc or 'q' to give up, any other key to retry:%s",fl_end); do_fflush();
 					if ((ch = next_con_char()) == 0x1b || ch == 0x3 || ch == 'q' || ch == 'Q') {
+						update_led_state(it, inst_led_off);
 						printf("\n");
 						it->del(it);
 						if (pfname != NULL)
@@ -2390,6 +2430,7 @@ a1log *log			/* verb, debug & error log */
 				empty_con_chars();
 				printf("\nAbort ? - Are you sure ? [y/n]:%s",fl_end); do_fflush();
 				if ((ch = next_con_char()) == 'y' || ch == 'Y') {
+					update_led_state(it, inst_led_off);
 					printf("\n");
 					it->del(it);
 					if (pfname != NULL)
@@ -2401,7 +2442,9 @@ a1log *log			/* verb, debug & error log */
 			} else if (ch == 'k') {
 				inst_code ev;
 
+				update_led_state(it, inst_led_cal_wait);
 				ev = inst_handle_calibrate(it, inst_calt_available, inst_calc_none, NULL, NULL, 0);
+				update_led_state(it, inst_led_off);
 				if (ev != inst_ok) {	/* Abort or fatal error */
 					it->del(it);
 					if (pfname != NULL)
@@ -2556,6 +2599,7 @@ a1log *log			/* verb, debug & error log */
 	/* -------------------------------------------------- */
 
 	/* clean up */
+	update_led_state(it, inst_led_off);
 	if (it != NULL)
 		it->del(it);
 	if (pfname != NULL)
@@ -2621,7 +2665,7 @@ usage() {
 	}
 	fprintf(stderr," -T ratio         Modify strip patch consistency tolerance by ratio\n");
 	fprintf(stderr," -S               Suppress wrong strip & unexpected value warnings\n");
-//	fprintf(stderr," -Y U             Test i1pro2 UV measurement mode\n");
+	fprintf(stderr," -Y l             Enable i1Pro 2 visual LED feedback\n");
 	fprintf(stderr," -W n|h|x         Override serial port flow control: n = none, h = HW, x = Xon/Xoff\n");
 #ifndef SALONEINSTLIB
 	fprintf(stderr," -P               Plot spectral if patch by patch\n");
@@ -2902,7 +2946,9 @@ int main(int argc, char *argv[]) {
 				if (na == NULL)
 					usage();	/* "Parameter expected after -Y" */
 
-				{
+				if (na[0] == 'l' || na[0] == 'L') {
+					g_use_leds = 1;
+				} else {
 					usage();	/* "-Y parameter '%c' not recognised",na[0] */
 				}
 			}

spectro/conv.c

@@ -203,36 +203,37 @@ static int con_char(int wait) {
 		/* We assume pipe has been set to NOWAIT mode. */
 		} else if (stdin_type == FILE_TYPE_PIPE) {
 			int i, bib;
-//fprintf(stderr,"~1  top of pipe\n");
+			DWORD bytes_avail = 0;
+
+			/* Check available bytes in pipe before blocking */
+			if (!PeekNamedPipe(stdinh, NULL, 0, NULL, &bytes_avail, NULL) || bytes_avail == 0) {
+				if (!wait) {
+					return 0;
+				}
+			}
 
 			for (bib = 0; bib < 10;) {
-//fprintf(stderr,"~1  got %d in buf\n",bib);
+				if (!wait) {
+					if (!PeekNamedPipe(stdinh, NULL, 0, NULL, &bytes_avail, NULL) || bytes_avail == 0) {
+						break;
+					}
+				}
 				if ((!ReadFile(stdinh, buf + bib, 10 - bib, &bread, NULL) || bread == 0)
 				 && !wait) {
-//fprintf(stderr,"~1  no chars waiting\n");
 					break;
 				}
 				bib += bread;
 
 				for (i = 0; i < bib; i++) {
 					if (buf[i] == '\n' || buf[i] == '\r' || buf[i] == 0x3) {
-//fprintf(stderr,"~1  found lf at ix %d\n",i);
 						break;
 					}
 				}
 				if (i < bib) {
-//fprintf(stderr,"~1  found lf\n");
 					break;		/* Found '\n' */
 				}
 				Sleep(100);		/* Wait for a line ending in '\n' */
 			}
-
-//if (bread > 0) {
-//fprintf(stderr,"~1  read %d: ",bread);
-//for (i = 0; i < bread; i++)
-//fprintf(stderr," 0x%x",buf[i]);
-//fprintf(stderr,"\n//");
-//}
 			rv = buf[0];
 
 		/* Assume a file. This will have very limited functionality. */

spectro/i1pro.c

@@ -170,9 +170,14 @@ i1pro_determine_capabilities(i1pro *p) {
 			| inst2_user_switch_trig
 			| inst2_bidi_scan
 			| inst2_has_scan_toll
-			| inst2_no_feedback
 	        ;
 
+	if (p->dtype == instI1Pro2) {
+		p->cap2 |= inst2_has_leds;
+	} else {
+		p->cap2 |= inst2_no_feedback;
+	}
+
 	if (p->m != NULL) {
 		i1proimp *m = (i1proimp *)p->m;
 		i1pro_state *s = &m->ms[m->mmode];
@@ -943,11 +948,24 @@ i1pro_get_set_opt(inst *pp, inst_opt_type m, ...) {
 	}
 }
 
+/* Set device indicator LED status */
+static inst_code
+i1pro_set_led_state(inst *pp, inst_led_state state) {
+	i1pro *p = (i1pro *)pp;
+
+	if (p->dtype != instI1Pro2)
+		return inst_unsupported;
+
+	return i1pro_interp_code(p, i1pro_imp_set_led_state(p, state));
+}
+
 /* Destroy ourselves */
 static void
 i1pro_del(inst *pp) {
 	i1pro *p = (i1pro *)pp;
 
+	/* Shut down instrument hardware and close the port, then free state */
+	i1pro_close_port(p);
 	del_i1proimp(p);
 	if (p->icom != NULL)
 		p->icom->del(p->icom);
@@ -982,6 +1000,7 @@ extern i1pro *new_i1pro(icoms *icom, instType dtype) {
 	p->meas_delay        = i1pro_meas_delay;
 	p->white_change      = i1pro_white_change;
 	p->interp_error      = i1pro_interp_error;
+	p->set_led_state     = i1pro_set_led_state;
 	p->del               = i1pro_del;
 
 	p->icom = icom;

spectro/i1pro_imp.c

@@ -389,8 +389,121 @@ i1pro_code add_i1proimp(i1pro *p) {
 	return I1PRO_OK;
 }
 
-/* Shutdown instrument, and then destroy */
-/* implementation structure */
+/* Stop background threads (switch monitoring & delayed trigger) */
+static void
+i1pro_stop_threads(i1pro *p) {
+	i1proimp *m;
+	int i;
+
+	if (p == NULL || p->m == NULL)
+		return;
+	m = (i1proimp *)p->m;
+
+	/* Stop the switch monitoring thread first so it isn't using the */
+	/* communication channel while we shut down the instrument. */
+	if (m->th != NULL) {
+		m->th_term = 1;			/* Tell thread to exit on error */
+
+		/* Ask the instrument to stop sending switch events and cancel */
+		/* any outstanding switch read. Only do this if the port is still  */
+		/* open and the required method pointers are valid. */
+		if (p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL
+		 && p->icom->usb_cancel_io != NULL) {
+			i1pro_terminate_switch(p);
+		}
+
+		/* Give the thread a chance to exit cleanly (up to 5 seconds). */
+		for (i = 0; m->th_termed == 0 && i < 100; i++)
+			msec_sleep(50);
+
+		if (m->th_termed == 0) {
+			a1logd(p->log,3,"i1pro switch thread did not terminate, forcing\n");
+			if (m->th->terminate != NULL)
+				m->th->terminate(m->th);
+		}
+
+		if (m->th->wait != NULL)
+			m->th->wait(m->th);
+		if (m->th->del != NULL)
+			m->th->del(m->th);
+		m->th = NULL;
+
+		usb_uninit_cancel(&m->sw_cancel);		/* Don't need cancel token now */
+		usb_uninit_cancel(&m->rd_sync);			/* Don't need sync token now */
+		a1logd(p->log,5,"i1pro switch thread terminated\n");
+	}
+
+	/* Stop the delayed trigger thread if it is still running */
+	if (m->trig_thread != NULL) {
+		if (m->trig_thread->wait != NULL)
+			m->trig_thread->wait(m->trig_thread);
+		if (m->trig_thread->del != NULL)
+			m->trig_thread->del(m->trig_thread);
+		m->trig_thread = NULL;
+		a1logd(p->log,5,"i1pro trigger thread terminated\n");
+	}
+
+	/* Stop the LED status feedback thread if running */
+	if (m->led_th != NULL) {
+		m->led_th_run = 0;
+		if (m->led_th->wait != NULL)
+			m->led_th->wait(m->led_th);
+		if (m->led_th->del != NULL)
+			m->led_th->del(m->led_th);
+		m->led_th = NULL;
+		a1logd(p->log,5,"i1pro led thread terminated\n");
+	}
+	if (m->led_th_init) {
+		amutex_del(m->led_lock);
+		m->led_th_init = 0;
+	}
+}
+
+/* Stop any pending I/O, shut down the instrument hardware, and close the */
+/* communication port. This is separate from freeing the implementation data. */
+i1pro_code
+i1pro_close_port(i1pro *p) {
+	i1pro_code ev = I1PRO_OK;
+	i1proimp *m;
+
+	a1logd(p->log,3,"i1pro_close_port: called\n");
+
+	if (p->m == NULL)
+		return I1PRO_OK;
+	m = (i1proimp *)p->m;
+
+	/* Stop the switch monitoring thread and trigger thread first so they */
+	/* aren't using the communication channel while we shut down the instrument. */
+	i1pro_stop_threads(p);
+
+	/* Update usage log/calibration for Rev A..D before closing the port */
+	if (p->dtype != instI1Pro2 && p->icom != NULL && p->icom->is_open
+	 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+		i1pro_code uev;
+		if ((uev = i1pro_update_log(p)) != I1PRO_OK) {
+			a1logd(p->log,2,"i1pro_update_log: Updating the cal and log parameters to"
+			                                              " EEProm failed failed\n");
+		}
+	}
+
+	/* Turn off i1Pro2/Rev E indicator LEDs before closing the port. */
+	/* Only attempt the write if the port is still actively open and the */
+	/* required USB method pointers are valid. Rev A..D do not have LEDs. */
+	if (p->dtype == instI1Pro2 && p->icom != NULL && p->icom->is_open
+	 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+		i1pro2_indLEDoff(p);	/* Ignore error - we're shutting down */
+	}
+
+	/* Close the underlying communication port */
+	if (p->icom != NULL && p->icom->is_open && p->icom->close_port != NULL) {
+		p->icom->close_port(p->icom);
+	}
+
+	return ev;
+}
+
+/* Destroy implementation structure */
 void del_i1proimp(i1pro *p) {
 
 	a1logd(p->log,5,"i1pro_del called\n");
@@ -404,38 +517,28 @@ void del_i1proimp(i1pro *p) {
 		int i, j;
 		i1proimp *m = (i1proimp *)p->m;
 		i1pro_state *s;
-		i1pro_code ev;
 
-		if (p->dtype != instI1Pro2 && (ev = i1pro_update_log(p)) != I1PRO_OK) {
+		/* Defensive guard: ensure background threads are terminated and joined */
+		/* before freeing state, in case i1pro_close_port() was not called. */
+		i1pro_stop_threads(p);
+
+		/* Defensive guard: update usage log/cal for Rev A..D if port is still open */
+		if (p->dtype != instI1Pro2 && p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+			i1pro_code uev;
+			if ((uev = i1pro_update_log(p)) != I1PRO_OK) {
 				a1logd(p->log,2,"i1pro_update_log: Updating the cal and log parameters to"
 				                                              " EEProm failed failed\n");
 			}
-
-		/* i1pro_terminate_switch() seems to fail on a rev A & Rev C ?? */
-		if (m->th != NULL) {		/* Terminate switch monitor thread */
-			m->th_term = 1;			/* Tell thread to exit on error */
-			i1pro_terminate_switch(p);
-			
-			for (i = 0; m->th_termed == 0 && i < 5; i++)
-				msec_sleep(50);		/* Wait for thread to terminate */
-			if (i >= 5) {
-				a1logd(p->log,5,"i1pro switch thread termination failed\n");
-				m->th->terminate(m->th);	/* Try and force thread to terminate */
-			}
-			/* Strange Mac M2/rosetta bug ?? */
-			if (m->th->del == NULL) {
-				a1logd(p->log,1,"i1pro_del: ,m->th-del is NULL!!!");
-			} else {
-				m->th->del(m->th);
-			}
-			usb_uninit_cancel(&m->sw_cancel);		/* Don't need cancel token now */
-			usb_uninit_cancel(&m->rd_sync);			/* Don't need sync token now */
-			a1logd(p->log,5,"i1pro switch thread terminated\n");
 		}
 
-		if (m->trig_thread != NULL) {
-			m->trig_thread->del(m->trig_thread);
-			a1logd(p->log,5,"i1pro trigger thread terminated\n");
+		/* Defensive guard: if the com port is still open and this is an */
+		/* i1Pro2, make sure the indicator LEDs are turned off before any */
+		/* memory is freed. In normal teardown i1pro_close_port() has */
+		/* already done this, but the guard protects any direct call paths. */
+		if (p->dtype == instI1Pro2 && p->icom != NULL && p->icom->is_open
+		 && p->icom->usb_control != NULL && p->icom->usb_write != NULL) {
+			i1pro2_indLEDoff(p);
 		}
 
 		/* Free any per mode data */
@@ -12319,11 +12422,17 @@ i1pro2_stop_ruler(void *pp, int parm) {
 static int
 i1pro2_indLEDseq(void *pp, unsigned char *buf, int size) {
 	i1pro *p = (i1pro *)pp;
-	i1proimp *m = (i1proimp *)p->m;
+	i1proimp *m;
 	int rwbytes;			/* Data bytes written */
 	unsigned char pbuf[4];	/* Number of bytes being send */
 	int se, rv = I1PRO_OK;
 
+	if (p == NULL || p->m == NULL || p->icom == NULL || !p->icom->is_open
+	 || p->icom->usb_control == NULL || p->icom->usb_write == NULL) {
+		return I1PRO_INT_NO_COMS;
+	}
+	m = (i1proimp *)p->m;
+
 	int2buf(pbuf, size); 
 
 	a1logd(p->log,2,"i1pro2_indLEDseq: length %d bytes\n", size);
@@ -12377,6 +12486,173 @@ i1pro2_indLEDoff(void *pp) {
 	return rv;
 }
 
+/* Set indicator LEDs to a solid color mask (or off if mask is 0) */
+static int
+i1pro2_indLEDset(void *pp, unsigned char mask) {
+	i1pro *p = (i1pro *)pp;
+	int rv = I1PRO_OK;
+	unsigned char seq[] = {
+		0x00, 0x00, 0x00, 0x01,
+
+		0x00, 0x00, 0x00, 0x0a,
+		0xff, 0xff, 0xff, 0xff,
+		0x00, 0x36, 0x40,
+		0x00, 0x00, 0x01
+	};
+
+	if (mask == 0)
+		return i1pro2_indLEDoff(pp);
+
+	seq[12] = mask;
+
+	a1logd(p->log,3,"i1pro2_indLEDset: called with mask 0x%02x\n", mask);
+	rv = i1pro2_indLEDseq(p, seq, sizeof(seq));
+	a1logd(p->log,3,"i1pro2_indLEDset: returning ICOM err 0x%x\n", rv);
+
+	return rv;
+}
+
+/* Helper to sleep up to ms while checking if state changed or thread stopping */
+static void
+led_sleep_ms(i1proimp *m, inst_led_state state, int ms) {
+	int elapsed = 0;
+	while (m->led_th_run && elapsed < ms) {
+		inst_led_state cur;
+		amutex_lock(m->led_lock);
+		cur = m->current_led_state;
+		amutex_unlock(m->led_lock);
+		if (cur != state)
+			break;
+		msec_sleep(20);
+		elapsed += 20;
+	}
+}
+
+/* Worker thread for asynchronous LED pulsing / patterns */
+static int
+i1pro2_led_thread(void *context) {
+	i1pro *p = (i1pro *)context;
+	i1proimp *m;
+	int phase = 0;
+	int i;
+
+	if (p == NULL || p->m == NULL)
+		return 0;
+	m = (i1proimp *)p->m;
+
+	a1logd(p->log, 3, "i1pro2_led_thread started\n");
+
+	while (m->led_th_run) {
+		inst_led_state state;
+
+		amutex_lock(m->led_lock);
+		state = m->current_led_state;
+		amutex_unlock(m->led_lock);
+
+		switch (state) {
+			case inst_led_cal_wait:
+				/* White flashing: 500ms ON / 500ms OFF (1.0 Hz) */
+				if (phase % 2 == 0)
+					i1pro2_indLEDset(p, 0x3F);		/* White = both Red+Green+Blue */
+				else
+					i1pro2_indLEDoff(p);
+				led_sleep_ms(m, inst_led_cal_wait, 500);
+				phase++;
+				break;
+
+			case inst_led_row_ready:
+				/* Blue pulsing: 300ms ON / 700ms OFF (1.0 Hz) */
+				i1pro2_indLEDset(p, 0x24);			/* Blue = both Left & Right Blue */
+				led_sleep_ms(m, inst_led_row_ready, 300);
+				i1pro2_indLEDoff(p);
+				led_sleep_ms(m, inst_led_row_ready, 700);
+				phase = 0;
+				break;
+
+			case inst_led_row_fail:
+				/* Red rapid strobe: 3 short bursts (100ms ON / 100ms OFF, 600ms total) */
+				for (i = 0; i < 3 && m->led_th_run; i++) {
+					i1pro2_indLEDset(p, 0x09);		/* Red = both Left & Right Red */
+					msec_sleep(100);
+					i1pro2_indLEDoff(p);
+					msec_sleep(100);
+				}
+				/* Revert to off until next command */
+				amutex_lock(m->led_lock);
+				if (m->current_led_state == inst_led_row_fail)
+					m->current_led_state = inst_led_off;
+				amutex_unlock(m->led_lock);
+				phase = 0;
+				break;
+
+			case inst_led_row_success:
+				/* Green pulse: Solid confirmation illumination for 400ms */
+				i1pro2_indLEDset(p, 0x12);			/* Green = both Left & Right Green */
+				msec_sleep(400);
+				i1pro2_indLEDoff(p);
+
+				/* Revert to off until next command */
+				amutex_lock(m->led_lock);
+				if (m->current_led_state == inst_led_row_success)
+					m->current_led_state = inst_led_off;
+				amutex_unlock(m->led_lock);
+				phase = 0;
+				break;
+
+			case inst_led_off:
+			default:
+				i1pro2_indLEDoff(p);
+				led_sleep_ms(m, inst_led_off, 100);
+				phase = 0;
+				break;
+		}
+	}
+
+	/* Extinguish LEDs upon thread exit if port is still open */
+	if (p->icom != NULL && p->icom->is_open)
+		i1pro2_indLEDoff(p);
+
+	a1logd(p->log, 3, "i1pro2_led_thread exiting\n");
+	return 0;
+}
+
+/* Set indicator LED status */
+i1pro_code
+i1pro_imp_set_led_state(i1pro *p, inst_led_state state) {
+	i1proimp *m;
+
+	if (p == NULL || p->m == NULL)
+		return I1PRO_INT_NO_COMS;
+	m = (i1proimp *)p->m;
+
+	if (p->dtype != instI1Pro2)
+		return I1PRO_UNSUPPORTED;
+
+	if (!m->led_th_init) {
+		amutex_init(m->led_lock);
+		m->led_th_init = 1;
+	}
+
+	amutex_lock(m->led_lock);
+	m->current_led_state = state;
+	amutex_unlock(m->led_lock);
+
+	/* If thread is not yet running and state is not off, start worker thread */
+	if (m->led_th == NULL && state != inst_led_off) {
+		m->led_th_run = 1;
+		if ((m->led_th = new_athread(i1pro2_led_thread, (void *)p)) == NULL) {
+			a1logd(p->log, 1, "i1pro_imp_set_led_state: new_athread failed\n");
+			return I1PRO_INT_THREADFAILED;
+		}
+	} else if (state == inst_led_off && m->led_th == NULL) {
+		/* Directly extinguish LEDs if port is open */
+		if (p->icom != NULL && p->icom->is_open)
+			i1pro2_indLEDoff(p);
+	}
+
+	return I1PRO_OK;
+}
+
 #ifdef NEVER
 
 	// ~~99 play with LED settings

spectro/i1pro_imp.h

@@ -340,6 +340,13 @@ struct _i1proimp {
 	volatile double whitestamp;	/* meas_delay() white timestamp */
 	volatile double trigstamp;	/* meas_delay() trigger timestamp */
 
+	/* Visual LED feedback thread management */
+	athread        *led_th;
+	int             led_th_run;
+	int             led_th_init;
+	amutex          led_lock;
+	inst_led_state  current_led_state;
+
 }; typedef struct _i1proimp i1proimp;
 
 /* Add an implementation structure */
@@ -348,6 +355,9 @@ i1pro_code add_i1proimp(i1pro *p);
 /* Destroy implementation structure */
 void del_i1proimp(i1pro *p);
 
+/* Close instrument (stop threads, update log, turn off LEDs, close coms) */
+i1pro_code i1pro_close_port(i1pro *p);
+
 /* ============================================================ */
 /* Error codes returned from i1pro_imp */
 
@@ -532,6 +542,8 @@ i1pro_code i1pro_set_stdres(i1pro *p);
 /* Modify the scan consistency tollerance */
 i1pro_code i1pro_set_scan_toll(i1pro *p, double toll_ratio);
 
+/* Set device indicator LED status */
+i1pro_code i1pro_imp_set_led_state(i1pro *p, inst_led_state state);
 
 /* Update the single remission calibration and instrument usage log */
 i1pro_code i1pro_update_log(i1pro *p);

spectro/inst.c

@@ -589,6 +589,11 @@ static inst_config config_enum(inst *p, int ec) {
 	return inst_conf_unknown;
 }
 
+/* Set device indicator LED status (default implementation) */
+static inst_code set_led_state(inst *p, inst_led_state state) {
+	return inst_unsupported;
+}
+
 /* ---------------------------------------------- */
 
 /* Delete things set/done by new_inst() */
@@ -824,6 +829,8 @@ void *cntx			/* Context for callback */
 		p->last_scomerr = last_scomerr;
 	if (p->config_enum == NULL)
 		p->config_enum = config_enum;
+	if (p->set_led_state == NULL)
+		p->set_led_state = set_led_state;
 
 	/* Set the provided user interaction callback */
 	p->set_uicallback(p, uicallback, cntx);

spectro/inst.h

@@ -371,6 +371,9 @@ typedef enum {
 
 } inst2_capability;
 
+/* Capability alias for instrument indicator LED status feedback */
+#define INST_CAP_LED_STATUS inst2_has_leds
+
 /* Instrument capabilities 3 (room for expansion) */
 /* (Available capabilities may be mode dependent) */
 typedef enum {
@@ -558,6 +561,15 @@ typedef enum {
 
 } inst_opt_type;
 
+/* Generic Instrument LED Status States */
+typedef enum {
+	inst_led_off           = 0,
+	inst_led_cal_wait      = 1, /* Flashing White */
+	inst_led_row_ready     = 2, /* Flashing Blue  */
+	inst_led_row_fail      = 3, /* Flashing Red   */
+	inst_led_row_success   = 4  /* Solid/Flash Green */
+} inst_led_state;
+
 /* Optional manufacturers instrument filter fitted to instrument (for inst_opt_set_filter) */
 /* These could be physical (i.e. Spectrolino, i1Pro3), or they could be virtual (i.e. i1Pro3) */  
 typedef enum {
@@ -1170,6 +1182,9 @@ typedef struct _inst_meascondsel {
 	/* (This is used for deciding fallback/retry strategies) */					\
 	int (*last_scomerr)(struct _inst *p);										\
 																				\
+	/* Set device indicator LED status (if supported) */						\
+	inst_code (*set_led_state)(struct _inst *p, inst_led_state state);			\
+																				\
 	/* Destroy ourselves */														\
 	void (*del)(struct _inst *p);												\
 

tiff/Jamfile

@@ -31,12 +31,14 @@ ObjectKeep port/getopt.c ;
 ObjectKeep port/strcasecmp.c ;
 
 # generation utilities (don't use libport ! - there will be dependency problems for Xcompile!)
+if ! [ GLOB tiff/libtiff : tif_fax3sm.c ] {
 	if $(UNIX) {
 		Main mkg3states : libtiff/mkg3states.c [ CatPaths port : strcasecmp.c ] ;
 	} else {
 		Main mkg3states : libtiff/mkg3states.c [ CatPaths port : getopt.c strcasecmp.c ] ;
 	}
 	GenFileND libtiff/tif_fax3sm.c : mkg3states -c const [ NormPaths libtiff/tif_fax3sm.c ] ;
+}
 
 # support library for tools
 if $(UNIX) {