From d8bf317546bcfab0b6b50375218429fa9d470705 Mon Sep 17 00:00:00 2001
From: Lars Knoll <lars.knoll@digia.com>
Date: Tue, 1 Oct 2013 12:34:20 +0200
Subject: make qreal double by default on all platforms

On modern ARM CPUs there is no speed difference between
float and double anymore, so let's rather use double for
qreal to avoid rounding and precision issues. Like this
we also get much better compatibility with our desktop
OSes.

This is not binary compatible on ARM, but the old behavior
can be restored by passing -qreal float to configure.

Change-Id: I2a4b61e19a3dfa6b0bd76734cecf2634c97207fc
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 configure | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'configure')

diff --git a/configure b/configure
index b5e375baed..4adaa77403 100755
--- a/configure
+++ b/configure
@@ -1006,6 +1006,7 @@ QPA_PLATFORM_GUARD=yes
 CFG_CXX11=auto
 CFG_DIRECTWRITE=no
 CFG_WERROR=auto
+CFG_QREAL=double
 OPT_MAC_SDK=
 
 # initalize variables used for installation
@@ -1168,6 +1169,7 @@ while [ "$#" -gt 0 ]; do
     -mysql_config| \
     -qpa| \
     -qconfig| \
+    -qreal| \
     -android-sdk| \
     -android-ndk| \
     -android-ndk-platform| \
@@ -1419,6 +1421,9 @@ while [ "$#" -gt 0 ]; do
     qconfig)
         CFG_QCONFIG="$VAL"
         ;;
+    qreal)
+        CFG_QREAL="$VAL"
+        ;;
     sysroot)
         CFG_SYSROOT="$VAL"
         ;;
@@ -3699,6 +3704,9 @@ Additional options:
     -qconfig local ...... Use src/corelib/global/qconfig-local.h rather than the
                           default ($CFG_QCONFIG).
 
+    -qreal [double|float] typedef qreal to the specified type. The default is double.
+                          Note that changing this flag affects binary compatibility.
+
     -no-opengl .......... Do not support OpenGL.
     -opengl <api> ....... Enable OpenGL support
                           With no parameter, this will attempt to auto-detect
@@ -6356,6 +6364,10 @@ if [ "$CFG_LARGEFILE" = "yes" ] && [ "$XPLATFORM_MINGW" != "yes" ]; then
     echo "#define QT_LARGEFILE_SUPPORT 64" >>"$outpath/src/corelib/global/qconfig.h.new"
 fi
 
+if [ "$CFG_QREAL" != double ]; then
+    echo "#define QT_COORD_TYPE $CFG_QREAL" >>"$outpath/src/corelib/global/qconfig.h.new"
+fi
+
 if [ "$CFG_FRAMEWORK" = "yes" ]; then
     echo "#define QT_MAC_FRAMEWORK_BUILD" >>"$outpath/src/corelib/global/qconfig.h.new"
 fi
@@ -6960,6 +6972,10 @@ if [ "$ORIG_CFG_XKBCOMMON" != qt ] && [ "$CFG_XKBCOMMON" = qt ]; then
     echo "NOTE: libxkbcommon 0.2.0 (or higher) not found on the system, will use "
     echo "the bundled version from 3rd party directory."
 fi
+if [ "$CFG_QREAL" = double ] && [ "$CFG_ARCH" = arm ]; then
+    echo "NOTE: Qt is using double for qreal on this system. This is binary incompatible against Qt 5.1."
+    echo "Configure with '-qreal float' to create a build that is binary compatible with 5.1."
+fi
 
 exec 1>&3 3>&- # restore stdout
 cat $outpath/config.summary # display config feedback to user
-- 
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