--- a/configure.ac	Wed Mar 14 08:29:47 2018 +0100
+++ b/configure.ac	Wed Mar 14 12:27:19 2018 +0100
@@ -3341,6 +3341,7 @@
   Qt uic:                        $UIC $UICFLAGS
   Qt rcc:                        $RCC $RCCFLAGS
   Qt lrelease:                   $LRELEASE $LRELEASEFLAGS
+  Qt qhelpgenerator:             $QHELPGENERATOR $QHELPGENERATORFLAGS
   READLINE libraries:            $READLINE_LIBS
   Sndfile CPPFLAGS:              $SNDFILE_CPPFLAGS
   Sndfile LDFLAGS:               $SNDFILE_LDFLAGS

--- a/doc/doxyhtml/Doxyfile.in	Wed Mar 14 08:29:47 2018 +0100
+++ b/doc/doxyhtml/Doxyfile.in	Wed Mar 14 12:27:19 2018 +0100
@@ -489,6 +489,69 @@
 
 HTML_TIMESTAMP         = YES
 
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated that
+# can be used as input for Qt's qhelpgenerator to generate a Qt Compressed Help
+# (.qch) of the generated HTML documentation.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_QHP           = YES
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can be used to specify
+# the file name of the resulting .qch file. The path specified is relative to
+# the HTML output folder.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QCH_FILE               = ./octave-cpp-api.qch
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating Qt Help
+# Project output. For more information please see Qt Help Project / Namespace
+# (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#namespace).
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_NAMESPACE          = org.octave.cpp-api
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating Qt
+# Help Project output. For more information please see Qt Help Project / Virtual
+# Folders (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#virtual-
+# folders).
+# The default value is: doc.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_VIRTUAL_FOLDER     = doc
+
+# If the QHP_CUST_FILTER_NAME tag is set, it specifies the name of a custom
+# filter to add. For more information please see Qt Help Project / Custom
+# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_NAME   = "Octave C++ API"
+
+# The QHP_CUST_FILTER_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see Qt Help Project / Custom
+# Filters (see: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-
+# filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_ATTRS  = "core cpp"
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's filter section matches. Qt Help Project / Filter Attributes (see:
+# http://qt-project.org/doc/qt-4.8/qthelpproject.html#filter-attributes).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_SECT_FILTER_ATTRS  = "core cpp"
+
+# The QHG_LOCATION tag can be used to specify the location of Qt's
+# qhelpgenerator. If non-empty doxygen will try to run qhelpgenerator on the
+# generated .qhp file.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHG_LOCATION           = @QHELPGENERATOR@
+
 # If you want full control over the layout of the generated HTML pages it might
 # be necessary to disable the index and replace it with your own. The
 # DISABLE_INDEX tag can be used to turn on/off the condensed index (tabs) at top

--- a/m4/acinclude.m4	Wed Mar 14 08:29:47 2018 +0100
+++ b/m4/acinclude.m4	Wed Mar 14 12:27:19 2018 +0100
@@ -1922,17 +1922,29 @@
       LRELEASE="$LRELEASE_QTVER"
     fi
 
-    if test -z "$MOC" || test -z "$UIC" || test -z "$RCC" || test -z "$LRELEASE"; then
+    AC_CHECK_TOOLS(QHELPGENERATOR_QTVER, [qhelpgenerator-qt$qt_version])
+    if test -z "$QHELPGENERATOR_QTVER"; then
+      AC_CHECK_TOOLS(QHELPGENERATOR, [qhelpgenerator])
+      if test -n "$QHELPGENERATOR" && test -n "$QTCHOOSER"; then
+        QHELPGENERATORFLAGS="-qt$qt_version"
+      fi
+    else
+      QHELPGENERATOR="$QHELPGENERATOR_QTVER"
+    fi
+
+    if test -z "$MOC" || test -z "$UIC" || test -z "$RCC" || test -z "$LRELEASE" || test -z "$QHELPGENERATOR"; then
       warn_qt_tools="one or more of the Qt utility programs moc, uic, rcc, and lrelease not found; disabling Qt GUI"
       build_qt_gui=no
       MOC_QTVER=
       UIC_QTVER=
       RCC_QTVER=
       LRELEASE_QTVER=
-      MOC_FLAGS=
-      UIC_FLAGS=
-      RCC_FLAGS=
-      LRELEASE_FLAGS=
+      QHELPGENERATOR_QTVER=
+      MOCFLAGS=
+      UICFLAGS=
+      RCCFLAGS=
+      LRELEASEFLAGS=
+      QHELPGENERATORFLAGS=
       $as_unset ac_cv_prog_MOC_QTVER
       $as_unset ac_cv_prog_ac_ct_MOC_QTVER
       $as_unset ac_cv_prog_UIC_QTVER
@@ -1941,6 +1953,8 @@
       $as_unset ac_cv_prog_ac_ct_RCC_QTVER
       $as_unset ac_cv_prog_LRELEASE_QTVER
       $as_unset ac_cv_prog_ac_ct_LRELEASE_QTVER
+      $as_unset ac_cv_prog_QHELPGENERATOR_QTVER
+      $as_unset ac_cv_prog_ac_ct_QHELPGENERATOR_QTVER
     fi
   fi