Many modern Android devices (i.e. Nexus 5x) have **AArch64** processors with **arm64-v8a** instruction set.  Both - `armeabi` and `armeabi-v7a` - libraries run fine on these modern devices.  Therefore, we can assume the answer to your question to be &#39;YES&#39;.

See this for a breakdown of ABI management on Android: https://developer.android.com/ndk/guides/abis.html  

I have a pretty straight-forward range input slider.  It works pretty well on all browsers except on iOS Safari.  

The main problem I have is when I click on the slider track, it doesn&#39;t move the slider.  It merely highlights the slider.  It works fine when dragging the thumb.  Any ideas on how to fix this?

    &lt;div class=&quot;slider-wrap&quot;&gt;
    	&lt;div id=&quot;subtractBtn&quot;&gt;&lt;/div&gt;
	    &lt;input type=&quot;range&quot; class=&quot;slider&quot;&gt;
     	&lt;div id=&quot;addBtn&quot;&gt;&lt;/div&gt;
    &lt;/div&gt;

Input range slider not working on iOS Safari when clicking on track

I&#180;m running pure JUnit4 java tests over my pure java files on my project but I can&#39;t find a way to use [@VisibleForTesting][1] clearly without making the thing manually public.

Ex:

    @VisibleForTesting
    public Address getAddress() {
      return mAddress;
    }

The method has to be `public` to let it be &quot;public&quot; to tests, but in that case the annotation doesn&#39;t make sense right? why not just use a comment if the annotation will not do nothing?

  [1]: https://developer.android.com/intl/es/reference/android/support/annotation/VisibleForTesting.html

How to use VisibleForTesting for pure JUnit tests

For my Android-app I&#39;m using the ABI &quot;x86&quot; and &quot;armeabi&quot; right now.
The armeabi is used for all ARM-devices, including armv7a and arm64-v8a.

Now I would like to remove the &quot;armeabi&quot; and just continue with &quot;x86&quot; and &quot;armeabi-v7a&quot;.

I haven&#39;t found any hint in the docs, that ARMv8 is also compatible with ARMv7 - can anyone confirm that my app will still work on devices running arm64-v8a, if I don&#39;t offer an armeabi but now an armeabi-v7a-library?



Is arm64-v8a compatible with armeabi-v7a?

For my Android-app I'm using the ABI "x86" and "armeabi" right now.
The armeabi is used for all ARM-devices, including armv7a and arm64-v8a.
Now I would like to remove the "armeabi" and just continue with "x86" and "armeabi-v7a".
I haven't found any hint in the docs, that ARMv8 is also compatible with ARMv7 - can anyone confirm that my app will still work on devices running arm64-v8a, if I don't offer an armeabi but now an armeabi-v7a-library?

The `RecyclerView.scrollToPosition()` is extremely strange.
for example, supposed a `RecyclerView` named `&quot;rv&quot;`.

 1. if now item 10 is under the current `RecyclerView`, call `rv.scrollToPosition(10)`, the `RecyclerView` will scroll item 10 to bottom.

 2. if now item 10 is in the current `RecyclerView`, call `rv.scrollToPosition(10)`, there won&#39;t be any scrolling, nothing will be done.

 3. if now item 10 is on the top of the current `RecyclerView`, call `rv.scrollToPosition(10)`, the `RecyclerView` will scroll item 10 to top.

To help understanding, look at this picture [![enter image description here][1]][1]


But what i need is that, whenever i call it, the `RecyclerView` will scroll the supposed position to the top of current view just like case 3. How to do that?

 


  [1]: https://i.stack.imgur.com/0JlFZ.png

How to use RecyclerView.scrollToPosition() to move the position to the top of current view?

With creation of [NestedScrollView](https://developer.android.com/reference/android/support/v4/widget/NestedScrollView.html) you can put scrolling view inside another scrolling view as long as those implement [NestedScrollingChild](https://developer.android.com/reference/android/support/v4/view/NestedScrollingChild.html) and [NestedScrollingParent](https://developer.android.com/reference/android/support/v4/view/NestedScrollingParent.html) correctly. 

(This is not bad design pattern &quot;Ian Lake (from Google) actually recommends putting a `RecyclerView` inside a nestedscrollview here: plus.google.com/u/0/+AndroidDevelopers/posts/9kZ3SsXdT2T&quot;) 

I want to put [RecyclerView](https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html) inside [NestedScrollView](https://developer.android.com/reference/android/support/v4/widget/NestedScrollView.html) and fortunately RecyclerView implements [NestedScrollingChild](https://developer.android.com/reference/android/support/v4/view/NestedScrollingChild.html) so you can put it inside [NestedScrollView](https://developer.android.com/reference/android/support/v4/widget/NestedScrollView.html).

    public class RecyclerView extends ViewGroup implements ScrollingView, NestedScrollingChild

 I have read these posts:

[How to use RecyclerView inside NestedScrollView?](https://stackoverflow.com/questions/31000081/how-to-use-recyclerview-inside-nestedscrollview)

[NestedScrolling with NestedScrollView, RecyclerView (Horizontal), inside a CoordinatorLayout](https://stackoverflow.com/questions/32448051/nestedscrolling-with-nestedscrollview-recyclerview-horizontal-inside-a-coord)

But the problem with most voted solution is, it calls all of the items of `RecyclerView` so for example if it is an endless RecyclerView and when the user reaches the end of the list you want to make a network request then with that solution the `RecyclerView` calls server repeatedly because it automatically reaches the last item of `RecyclerView`.

Anyway, how to set parameter so I can put `RecyclerView` inside `NestedScrollView`.(actually  I want to put a viewgroup like framelayout or relativelayout as a single childe of nestedscrollview and then I want to put recyclerview inside framelayout or relativelayout)

When I put `RecyclerView` inside `NestedScrollView` there is nothing to display.

---
In order to create a sample project you can use [cheesesquare](https://github.com/chrisbanes/cheesesquare) and change the `CheeseDetailActivity` to have a RecyclerView.

---

**Although the answer of BNK is not correct but BNK has tried a lot. So I award him the bounty. Still looking for nice solution....**






How to put RecyclerView inside NestedScrollView?

I&#39;am currently using `Retrofit 2` and i want to upload some photo at my server.
I know, that older version uses `TypedFile` class for uploading. And if we want to use progress bar with it we should override `writeTo` method in `TypedFile` class.

Is it possible to show progress when using `retrofit 2` library?

Is it possible to show progress bar when upload image via Retrofit 2?

I could not change the color of back button. I am using toolbar material design. In my app I am applying black background of tool bar but the back design is being black by default that&#39;s why I just want to change the color of this back button. Please give me solutions. 

Thank You

How to change color of Toolbar back button in Android?

I&#39;m trying to read NFC tags on my Android phone using the NFC module of Qt.

According to this [page][1], Qt will support NFC on Android starting from version 5.6. This version hasn&#39;t been released yet, so I built it from source, following the instructions on this [page][2], and installed it in Qt creator.

First step is to get the tag/card detection working and I&#39;m stuck there. My test application instantiates a `QNearFieldManager`, checks if NFC is available and connects slots to the signals `targetDetected` and `targetLost`.
The `QNearFieldManager::isAvailable` method reports that NFC is available (with Qt 5.5 it did not), but the signals `targetDetected`/`targetLost` are never fired.

Below is the code of my test application:

    #include &lt;QLabel&gt;
    #include &lt;QVBoxLayout&gt;
    
    #include &lt;QNearFieldManager&gt;
    #include &lt;QNearFieldTarget&gt;
    
    #include &lt;QDebug&gt;
    
    #include &quot;window.h&quot;
    
    Window::Window(QWidget *parent)
    : QWidget(parent)
    {
        nfcLabel_ = new QLabel(this);
    
        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout-&gt;addWidget(nfcLabel_, 1);
    
        setLayout(mainLayout);
    
        setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed));
    
        setWindowTitle(tr(&quot;NFC Test&quot;));
    
        nfc_ = new QNearFieldManager(this);
        if (nfc_-&gt;isAvailable()) {
            nfcLabel_-&gt;setText(&quot;NFC available&quot;);
        } else {
            nfcLabel_-&gt;setText(&quot;NFC not available&quot;);
            qWarning() &lt;&lt; &quot;NFC not available&quot;;
        }

        nfc_-&gt;setTargetAccessModes(QNearFieldManager::NdefReadTargetAccess); // doesn&#39;t help
    
        nfc_-&gt;registerNdefMessageHandler(this, SLOT(handleNdefMessage(QNdefMessage,QNearFieldTarget*))); // doesn&#39;t help
    
        connect(nfc_, SIGNAL(targetDetected(QNearFieldTarget*)), this, SLOT(targetDetected(QNearFieldTarget*)));
        connect(nfc_, SIGNAL(targetLost(QNearFieldTarget*)), this, SLOT(targetLost(QNearFieldTarget*)));
    
        if (!nfc_-&gt;startTargetDetection()) {
            qWarning() &lt;&lt; &quot;NFC target detection could not be started&quot;;
        }
    }
    
    Window::~Window()
    {
        nfc_-&gt;stopTargetDetection();
    }
    
    void Window::targetDetected(QNearFieldTarget * /*target*/)
    {
        nfcLabel_-&gt;setText(&quot;Target detected&quot;);
    }
    
    void Window::targetLost(QNearFieldTarget *target)
    {
        nfcLabel_-&gt;setText(&quot;Target lost&quot;);
        target-&gt;deleteLater();
    }
    
    void Window::handleNdefMessage(const QNdefMessage &amp;/*message*/, QNearFieldTarget */*target*/)
    {
        qDebug() &lt;&lt; &quot;Ndef Message&quot;;
    }
    

I must be missing something...

**UPDATE 1**

It appears that the AndroidManifest.xml file needs to be modified. I tried different things, but none seem to produce the desired effect. I can only get the `targetDetected` and `targetLost` events to fire when the manifest defines an intent-filter like this:

    &lt;intent-filter&gt;
        &lt;action android:name=&quot;android.nfc.action.TAG_DISCOVERED&quot;/&gt;
        &lt;category android:name=&quot;android.intent.category.DEFAULT&quot;/&gt;
    &lt;/intent-filter&gt;
    
However, this also causes the app to be started each time a target is scanned, even if the app is already running. What I need is to start the app and then wait for a target to be scanned. How can I accomplish this?

**UPDATE 2**

Below is the full AndroidManifest.xml file that I tried.

    &lt;?xml version=&quot;1.0&quot;?&gt;
    &lt;manifest package=&quot;org.qtproject.example&quot; xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot; android:versionName=&quot;1.0&quot; android:versionCode=&quot;1&quot; android:installLocation=&quot;auto&quot;&gt;
        &lt;application android:hardwareAccelerated=&quot;true&quot; android:name=&quot;org.qtproject.qt5.android.bindings.QtApplication&quot; android:label=&quot;-- %%INSERT_APP_NAME%% --&quot; android:theme=&quot;@android:style/Theme.Holo&quot;&gt;
        &lt;activity android:configChanges=&quot;orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation&quot; android:name=&quot;org.qtproject.qt5.android.bindings.QtActivity&quot; android:label=&quot;-- %%INSERT_APP_NAME%% --&quot; android:screenOrientation=&quot;unspecified&quot; android:launchMode=&quot;singleTop&quot;&gt;
            &lt;intent-filter&gt;
            &lt;action android:name=&quot;android.intent.action.MAIN&quot;/&gt;
            &lt;category android:name=&quot;android.intent.category.LAUNCHER&quot;/&gt;
            &lt;/intent-filter&gt;
    
            &lt;!-- Without this, the targetDetected/targetLost signals aren&#39;t fired --&gt;
            &lt;intent-filter&gt;
            &lt;action android:name=&quot;android.nfc.action.TAG_DISCOVERED&quot;/&gt;
            &lt;category android:name=&quot;android.intent.category.DEFAULT&quot;/&gt;
            &lt;/intent-filter&gt;
    
            &lt;meta-data android:name=&quot;android.app.lib_name&quot; android:value=&quot;-- %%INSERT_APP_LIB_NAME%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.qt_sources_resource_id&quot; android:resource=&quot;@array/qt_sources&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.repository&quot; android:value=&quot;default&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.qt_libs_resource_id&quot; android:resource=&quot;@array/qt_libs&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_libs_resource_id&quot; android:resource=&quot;@array/bundled_libs&quot;/&gt;
            &lt;!-- Deploy Qt libs as part of package --&gt;
            &lt;meta-data android:name=&quot;android.app.bundle_local_qt_libs&quot; android:value=&quot;-- %%BUNDLE_LOCAL_QT_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_in_lib_resource_id&quot; android:resource=&quot;@array/bundled_in_lib&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_in_assets_resource_id&quot; android:resource=&quot;@array/bundled_in_assets&quot;/&gt;
            &lt;!-- Run with local libs --&gt;
            &lt;meta-data android:name=&quot;android.app.use_local_qt_libs&quot; android:value=&quot;-- %%USE_LOCAL_QT_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.libs_prefix&quot; android:value=&quot;/data/local/tmp/qt/&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.load_local_libs&quot; android:value=&quot;-- %%INSERT_LOCAL_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.load_local_jars&quot; android:value=&quot;-- %%INSERT_LOCAL_JARS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.static_init_classes&quot; android:value=&quot;-- %%INSERT_INIT_CLASSES%% --&quot;/&gt;
            &lt;!--  Messages maps --&gt;
            &lt;meta-data android:value=&quot;@string/ministro_not_found_msg&quot; android:name=&quot;android.app.ministro_not_found_msg&quot;/&gt;
            &lt;meta-data android:value=&quot;@string/ministro_needed_msg&quot; android:name=&quot;android.app.ministro_needed_msg&quot;/&gt;
            &lt;meta-data android:value=&quot;@string/fatal_error_msg&quot; android:name=&quot;android.app.fatal_error_msg&quot;/&gt;
            &lt;!--  Messages maps --&gt;
    
            &lt;!-- Splash screen --&gt;
            &lt;!--
            &lt;meta-data android:name=&quot;android.app.splash_screen_drawable&quot; android:resource=&quot;@drawable/logo&quot;/&gt;
            --&gt;
            &lt;!-- Splash screen --&gt;
    
            &lt;!-- Background running --&gt;
            &lt;!-- Warning: changing this value to true may cause unexpected crashes if the
                  application still try to draw after
                  &quot;applicationStateChanged(Qt::ApplicationSuspended)&quot;
                  signal is sent! --&gt;
            &lt;meta-data android:name=&quot;android.app.background_running&quot; android:value=&quot;false&quot;/&gt;
            &lt;!-- Background running --&gt;
        &lt;/activity&gt;
        &lt;/application&gt;
        &lt;uses-sdk android:minSdkVersion=&quot;10&quot; android:targetSdkVersion=&quot;14&quot;/&gt;
        &lt;supports-screens android:largeScreens=&quot;true&quot; android:normalScreens=&quot;true&quot; android:anyDensity=&quot;true&quot; android:smallScreens=&quot;true&quot;/&gt;
        &lt;uses-feature android:name=&quot;android.hardware.nfc&quot; android:required=&quot;true&quot;/&gt;
        &lt;uses-permission android:name=&quot;android.permission.NFC&quot;/&gt;
    &lt;/manifest&gt;
    

  [1]: https://wiki.qt.io/New_Features_in_Qt_5.6
  [2]: http://wiki.qt.io/Qt5ForAndroidBuilding

How to get NFC working on Android using Qt 5.6

I am wondering if a compatibility matrix exists between Springboot and Springcloud?

I created a simple project on STS and am running into compatibility issues. 

       &lt;parent&gt;
    		&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
    		&lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
    		&lt;version&gt;1.5.1.RELEASE&lt;/version&gt;
    		&lt;relativePath /&gt; &lt;!-- lookup parent from repository --&gt;
    	&lt;/parent&gt;


	&lt;dependencyManagement&gt;
		&lt;dependencies&gt;
			&lt;dependency&gt;
				&lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
				&lt;artifactId&gt;spring-cloud-dependencies&lt;/artifactId&gt;
				&lt;version&gt;Camden.SR5&lt;/version&gt;
				&lt;type&gt;pom&lt;/type&gt;
				&lt;scope&gt;import&lt;/scope&gt;
			&lt;/dependency&gt;
		&lt;/dependencies&gt;
	&lt;/dependencyManagement&gt;

Having a good view of the supported versions of both Springboot and Springcloud will make things simpler.

I did observe an open issue that talks about this need - https://github.com/spring-cloud/spring-cloud-build/issues/43

Does the community have an approach on how they choose to get started on a specific version combination when they embark on a SpringCloud project?

Edit: Adding another instance of such a problem that I encountered since yesterday

snippets from pom.xml

    &lt;parent&gt;
    		&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
    		&lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
    		 &lt;version&gt;1.5.2.RELEASE&lt;/version&gt;
    		&lt;!--&lt;version&gt;1.5.2.RELEASE&lt;/version&gt; --&gt;
    		&lt;relativePath /&gt; &lt;!-- lookup parent from repository --&gt;
    	&lt;/parent&gt;
    
    
    	&lt;dependencyManagement&gt;
    		&lt;dependencies&gt;
    			&lt;dependency&gt;
    				&lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
    				&lt;artifactId&gt;spring-cloud-dependencies&lt;/artifactId&gt;
    				&lt;!-- &lt;version&gt;Camden.SR6&lt;/version --&gt;
    				&lt;!-- &lt;version&gt;Brixton.SR5&lt;/version&gt; --&gt;
    				&lt;!--  &lt;version&gt;Camden.SR6&lt;/version&gt; --&gt;
    				&lt;version&gt;Camden.SR5&lt;/version&gt;
    				&lt;type&gt;pom&lt;/type&gt;
    				&lt;scope&gt;import&lt;/scope&gt;
    			&lt;/dependency&gt;
    		&lt;/dependencies&gt;
    	&lt;/dependencyManagement&gt;

There are no maven errors in using 1.5.2.RELEASE with Camden.SR5 however when the app starts it throws the NoClassDefFoundError.

    2017-03-28 09:51:15.148 ERROR 15808 --- [           main] o.s.boot.SpringApplication               : Application startup failed
    
    java.lang.NoClassDefFoundError: org/springframework/cloud/context/named/NamedContextFactory$Specification
    	at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_112]
    	at java.lang.ClassLoader.defineClass(ClassLoader.java:763) ~[na:1.8.0_112]
    	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_112]
    	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) ~[na:1.8.0_112]
    	at java.net.URLClassLoader.access$100(URLClassLoader.java:73) ~[na:1.8.0_112]
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:368) ~[na:1.8.0_112]
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:362) ~[na:1.8.0_112]
    	at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_112]
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:361) ~[na:1.8.0_112]
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_112]
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_112]
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_112]
    	at org.springframework.cloud.netflix.feign.FeignClientsRegistrar.registerClientConfiguration(FeignClientsRegistrar.java:367) ~[spring-cloud-netflix-core-1.2.5.RELEASE.jar:1.2.5.RELEASE]
    	at org.springframework.cloud.netflix.feign.FeignClientsRegistrar.registerDefaultConfiguration(FeignClientsRegistrar.java:104) ~[spring-cloud-netflix-core-1.2.5.RELEASE.jar:1.2.5.RELEASE]
    	at org.springframework.cloud.netflix.feign.FeignClientsRegistrar.registerBeanDefinitions(FeignClientsRegistrar.java:87) ~[spring-cloud-netflix-core-1.2.5.RELEASE.jar:1.2.5.RELEASE]
    	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsFromRegistrars(ConfigurationClassBeanDefinitionReader.java:352) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:143) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:116) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:320) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:270) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:93) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:686) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
    	at com.forecastessentials.school.SchoolUniformForecastApplication.main(SchoolUniformForecastApplication.java:12) [classes/:na]
    Caused by: java.lang.ClassNotFoundException: org.springframework.cloud.context.named.NamedContextFactory$Specification
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_112]
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_112]
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_112]
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_112]
    	... 31 common frames omitted


Using 1.4.5 with Brixton.SR6 is a combination that generally works well for me.

Is there a compatibility matrix of Spring-boot and Spring-cloud?

I am building a Angular4 project using Angular CLI (1.1.2). It runs perfectly in Chrome (Version 59.0.3071.115) and firefox(54.0.1) but when I tried to use IE11 (Verison 11.0.9600.18738) nothings shows up and when I open the develper mode in IE, it shows me the following Error:

    SCRIPT5022: Exception thrown and not caught
    File: polyfills.bundle.js, Line: 829, Column: 34

And the detailed Error message is following:

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/O2L2B.png


Anyone knows how to solve this problem?

Thanks!

Angular4 Application running issues in IE11

Is enabling Safe Area Layout Guides compatible to iOS below 11? 

[![enter image description here][1]][1]




  [1]: https://i.stack.imgur.com/FojCh.jpg

iOS 11 safe area layout guide backwards compatibility

I have noticed that some newer TensorFlow versions are incompatible with older CUDA and cuDNN versions. Does an overview of the compatible versions or even a list of officially tested combinations exist? I can&#39;t find it in the TensorFlow documentation. 

Which TensorFlow and CUDA version combinations are compatible?

`int 0x80` on Linux always invokes the 32-bit ABI, regardless of what mode it&#39;s called from:  args in `ebx`, `ecx`, ... and syscall numbers from `/usr/include/asm/unistd_32.h`.   (Or crashes on 64-bit kernels compiled without `CONFIG_IA32_EMULATION`).

**64-bit code should use `syscall`**, with call numbers from `/usr/include/asm/unistd_64.h`, and args in `rdi`, `rsi`, etc.  See https://stackoverflow.com/questions/2535989/what-are-the-calling-conventions-for-unix-linux-system-calls-on-x86-64.  If your question was marked a duplicate of this, **see that link for details on how you *should* make system calls in 32 or 64-bit code.**  If you want to understand what exactly happened, keep reading.

(For an example of 32-bit vs. 64-bit `sys_write`, see https://stackoverflow.com/questions/22503944/using-interrupt-0x80-on-64-bit-linux)

---

`syscall` system calls are faster than `int 0x80` system calls, so use native 64-bit `syscall` unless you&#39;re writing polyglot machine code that runs the same when executed as 32 or 64 bit.  (`sysenter` always returns in 32-bit mode, so it&#39;s not useful from 64-bit userspace, although it is a valid x86-64 instruction.)

Related: [**The Definitive Guide to Linux System Calls** (on x86)][1] for how to make `int 0x80` or `sysenter` 32-bit system calls, or `syscall` 64-bit system calls, or calling the vDSO for &quot;virtual&quot; system calls like `gettimeofday`.  Plus background on what system calls are all about.

---

Using `int 0x80` makes it possible to write something that will assemble in 32 or 64-bit mode, so it&#39;s handy for an `exit_group()` at the end of a microbenchmark or something.

Current PDFs of the official i386 and x86-64 System V psABI documents that standardize function and syscall calling conventions are linked from https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI.

See the [tag:x86] tag [wiki][2] for beginner guides, x86 manuals, official documentation, and performance optimization guides / resources.

----

But since people keep posting questions with code that uses [`int 0x80` in 64-bit code][3], or accidentally [building 64-bit binaries][4] from source written for 32-bit, I wonder **what *exactly* does happen on current Linux?**

**Does `int 0x80` save/restore all the 64-bit registers?  Does it truncate any registers to 32-bit?  What happens if you pass pointer args that have non-zero upper halves?**

**Does it work if you pass it 32-bit pointers?**


  [1]: https://blog.packagecloud.io/eng/2016/04/05/the-definitive-guide-to-linux-system-calls/
  [2]: https://stackoverflow.com/tags/x86/info
  [3]: https://stackoverflow.com/questions/14033028/sys-read-syscall-vs-int-0x80-in-gnu-assembler
  [4]: https://stackoverflow.com/questions/36861903/assembling-32-bit-binaries-on-a-64-bit-system-gnu-toolchain

What happens if you use the 32-bit int 0x80 Linux ABI in 64-bit code?

Suppose I have three compiled objects, all produced by the *same compiler/version*:

1. A was compiled with the C++11 standard
2. B was compiled with the C++14 standard
3. C was compiled with the C++17 standard

For simplicity, let&#39;s assume all headers were written in C++11, _using only constructs whose semantics haven&#39;t changed between all three standard versions_, and so any interdependencies were correctly expressed with header inclusion and the compiler did not object.

Which combinations of these objects is it and isn&#39;t it safe to link into a single binary? Why?

---
EDIT: answers covering major compilers (e.g. gcc, clang, vs++) are welcome

Is it safe to link C++17, C++14, and C++11 objects

### Background

In the last year I was using the nlohmann json library&lt;sup&gt;[1]&lt;/sup&gt; and was cross-compiling on x86_64 using GCC 5.x `arm-linux-gnueabi-*` with no warnings. When I updated GCC to a newer version, GCC would generate pages of cryptic diagnostic notes. For example, here is one of the notes

    In file included from /usr/arm-linux-gnueabi/include/c++/7/vector:69:0,
                 from include/json.hpp:58,
                 from src/write_hsi.cpp:23:
    /usr/arm-linux-gnueabi/include/c++/7/bits/vector.tcc: In member function ‘void std::vector&lt;_Tp, _Alloc&gt;::_M_realloc_insert(std::vector&lt;_Tp, _Alloc&gt;::iterator, _Args&amp;&amp; ...) [with _Args = {nlohmann::basic_json&lt;std::map, std::vector, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;, bool, long long int, long long unsigned int, double, std::allocator, nlohmann::adl_serializer&gt;}; _Tp = nlohmann::basic_json&lt;&gt;; _Alloc = std::allocator&lt;nlohmann::basic_json&lt;&gt; &gt;]’:
    /usr/arm-linux-gnueabi/include/c++/7/bits/vector.tcc:394:7: note: parameter passing for argument of type ‘std::vector&lt;nlohmann::basic_json&lt;&gt;, std::allocator&lt;nlohmann::basic_json&lt;&gt; &gt; &gt;::iterator {aka __gnu_cxx::__normal_iterator&lt;nlohmann::basic_json&lt;&gt;*, std::vector&lt;nlohmann::basic_json&lt;&gt;, std::allocator&lt;nlohmann::basic_json&lt;&gt; &gt; &gt; &gt;}’ changed in GCC 7.1
       vector&lt;_Tp, _Alloc&gt;::
       ^~~~~~~~~~~~~~~~~~~
    /usr/arm-linux-gnueabi/include/c++/7/bits/vector.tcc: In member function ‘nlohmann::basic_json&lt;ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer&gt; nlohmann::basic_json&lt;ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer&gt;::parser::parse_internal(bool) [with ObjectType = std::map; ArrayType = std::vector; StringType = std::__cxx11::basic_string&lt;char&gt;; BooleanType = bool; NumberIntegerType = long long int; NumberUnsignedType = long long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::adl_serializer]’:
    /usr/arm-linux-gnueabi/include/c++/7/bits/vector.tcc:105:21: note: parameter passing for argument of type ‘__gnu_cxx::__normal_iterator&lt;nlohmann::basic_json&lt;&gt;*, std::vector&lt;nlohmann::basic_json&lt;&gt;, std::allocator&lt;nlohmann::basic_json&lt;&gt; &gt; &gt; &gt;’ changed in GCC 7.1
    _M_realloc_insert(end(), std::forward&lt;_Args&gt;(__args)...);
    ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It was easy to find a solution, namely by adding `-Wno-psabi` to the compiler options. In fact, that was the fix implemented in the library.&lt;sup&gt;[2]&lt;/sup&gt;

I understand the basics of Application Binary Interfaces (ABIs) and processor-specific ABIs (psABIs). For reference, this answer&lt;sup&gt;[11]&lt;/sup&gt; gives a quick overview of ABIs:

&gt; An ABI (_**Application Binary Interface**_) is a standard that defines a mapping between low-level concepts in high-level languages and the abilities of a specific hardware/OS platform&#39;s machine code. That includes things like:
&gt; 
&gt;  - how C/C++/Fortran/... **data types** are laid out in memory (data sizes / alignments)
&gt;  - how nested **function calls** work (where and how the information on how to return to a function&#39;s caller is stored, where in the CPU registers and/or in memory function arguments are passed)
&gt;  - how **program startup / initialization** works (what data format an &quot;executable&quot; has, how the code / data is loaded from there, how DLLs work ...)
&gt; 
&gt; The answers to these are:
&gt; 
&gt;  - _language-specific_ (hence you&#39;ve got a C ABI, C++ ABI, Fortran ABI, Pascal ABI, ... even the Java bytecode spec, although targeting a &quot;virtual&quot; processor instead of real hardware, is an ABI),
&gt;  - _operating-system specific_ (MS Windows and Linux on the same hardware use a different ABI),
&gt;  - _hardware/CPU-specific_ (the ARM and x86 ABIs are different).
&gt;  - _evolving over (long) time_ (existing ABIs have often been updated / rev&#39;ed so that new CPU features could be made use of, like, say, specifying how the x86 SSE registers are to be used by apps was of course only possible once CPUs _had_ these regs, therefore existing ABIs needed to be clarified).

So the ABI is the overarching component, and one of its components (the &quot;hardware/CPU-specific&quot; details) is the psABI.

### My Issue

The problem I am having is

 1. I don&#39;t like universally disabling warnings without understanding the implications.
 2. The advice &quot;use `-Wno-psabi` to make the notes go away&quot; seems to be pretty common advice for these types of diagnostic notes that &quot;suddenly appear&quot; after a compiler upgrade.&lt;sup&gt;[2]&lt;/sup&gt;&lt;sup&gt;[3]&lt;/sup&gt;&lt;sup&gt;[4]&lt;/sup&gt; Even the one of the GCC developers suggest doing this.&lt;sup&gt;[5]&lt;/sup&gt;
 3. Neither `-Wpsabi` nor `-Wno-psabi` are documented&lt;sup&gt;[6]&lt;/sup&gt; in the GCC manual.&lt;sup&gt;[7]&lt;/sup&gt;

As a result I am not really sure what exactly `-Wno-psabi` will and will not affect. A related option `-Wabi` *is* documented:&lt;sup&gt;[8]&lt;/sup&gt;

&gt; `-Wabi (C, Objective-C, C++ and Objective-C++ only)`
&gt;
&gt;    Warn when G++ it generates code that is probably not compatible with the vendor-neutral C++ ABI...
&gt;
&gt; It also warns about psABI-related changes. The known psABI changes at this point include: 
&gt;
&gt; - For SysV/x86-64, unions with long double members are passed in memory as specified in psABI. For example: 
&gt;
&gt; `    union U {`
&gt; `     long double ld;`
&gt; `     int i;`
&gt; `    };`
&gt;
&gt; `union U` is always passed in memory.

My understanding of this all is

1. `-Wabi` will generate warnings when there is a psABI change.
2. GCC 7 fixed an ABI bug&lt;sup&gt;[9]&lt;/sup&gt; introduced in GCC 5 that affects ARM targets.
    - In the release notes it is stated &quot;this is an ABI change.&quot;&lt;sup&gt;[10]&lt;/sup&gt;
    - For some reason the release notes state that the related diagnostic notes are generated when using the undocumented `-Wpsabi`, not the documented `-Wabi`.
    - This ABI change is not mentioned in the manual.
3. Putting together &quot;this is an ABI change&quot; and &quot;use `-Wpsabi`&quot;, it appears to me this is *specifically* a psABI change, not a different kind of ABI change. (In reality it is a change in GCC&#39;s implementation of the psABI, not the psABI itself)

I know that documentation isn&#39;t always up to date, especially for something that is a known undocumented option. But my concern is that &quot;use `-Wno-psabi`&quot; seems to be the standard response for several different kinds of these cryptic diagnostic notes. But, in my basic understanding of ABIs, isn&#39;t an ABI change a big deal? Shouldn&#39;t I be concerned about an ABI change, rather than just making the message go away? Between the undocumented stuff and some of the finer details of ABI vs psABI, I&#39;m not really sure...

For example, if I add `-Wno-psabi` to my makefile to make those notes go away, what if there is another ABI change in the future that *does* affect my project? Have I effectively silenced future warnings or notes that may be important?

Also, even though we are told &quot;if you recompile all the code, there is nothing to worry about,&quot;&lt;sup&gt;[5]&lt;/sup&gt; what exactly is &quot;all the code&quot;? Is that my source code? glibc? Any other system-wide shared library I might be using?

### References

1. https://github.com/nlohmann/json
2. https://github.com/nlohmann/json/issues/658
3. https://stackoverflow.com/a/48149400
4. https://stackoverflow.com/a/13915796/10270632
5. https://gcc.gnu.org/ml/gcc/2017-05/msg00073.html
6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81831
7. https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gcc
8. https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gcc/C_002b_002b-Dialect-Options.html
9. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728
10. https://gcc.gnu.org/gcc-7/changes.html
11. https://stackoverflow.com/a/8063350

What exactly does GCC&#39;s -Wpsabi option do? What are the implications of supressing it?

I am constantly getting this warning while building my android studio code using terminal command `gradle clean assembleRelease`:

`Unable to strip library &#39;lib.so&#39; due to missing strip tool for ABI &#39;ARMEABI&#39;. Packaging it as is.`

Please help me on how to get this warning resolved.

Note: I know this won&#39;t affect the behaviour of my app, but my APK is too bulky and this will surely help me reduce APK size. So I need this resolved.

Android Studio : Missing Strip Tool

I know that an *&quot;undefined behaviour&quot;* in C++ can pretty much allow the compiler to do anything it wants. However, I had a crash that surprised me, as I assumed that the code was safe enough.

In this case, the real problem happened only on a specific platform using a specific compiler, and only if optimization was enabled.

I tried several things in order to reproduce the problem and simplify it to the maximum. Here&#39;s an extract of a function called `Serialize`, that would take a bool parameter, and copy the string `true` or `false` to an existing destination buffer.

Would this function be in a code review, there would be no way to tell that it, in fact, could crash if the bool parameter was an uninitialized value?

    // Zero-filled global buffer of 16 characters
    char destBuffer[16];
    
    void Serialize(bool boolValue) {
        // Determine which string to print based on boolValue
        const char* whichString = boolValue ? &quot;true&quot; : &quot;false&quot;;
        
        // Compute the length of the string we selected
        const size_t len = strlen(whichString);
        
        // Copy string into destination buffer, which is zero-filled (thus already null-terminated)
        memcpy(destBuffer, whichString, len);
    }

If this code is executed with clang 5.0.0 + optimizations, it will/can crash.

The expected ternary-operator `boolValue ? &quot;true&quot; : &quot;false&quot;` looked safe enough for me, I was assuming, &quot;Whatever garbage value is in `boolValue` doesn&#39;t matter, since it will evaluate to true or false anyhow.&quot;

I have setup a [Compiler Explorer example](https://godbolt.org/z/DoFmhA) that shows the problem in the disassembly, here the complete example. *Note: in order to repro the issue, the combination I&#39;ve found that worked is by using Clang 5.0.0 with -O2 optimisation.*

    #include &lt;iostream&gt;
    #include &lt;cstring&gt;
    
    // Simple struct, with an empty constructor that doesn&#39;t initialize anything
    struct FStruct {
        bool uninitializedBool;
        
       __attribute__ ((noinline))  // Note: the constructor must be declared noinline to trigger the problem
       FStruct() {};
    };
    
    char destBuffer[16];
    
    // Small utility function that allocates and returns a string &quot;true&quot; or &quot;false&quot; depending on the value of the parameter
    void Serialize(bool boolValue) {
        // Determine which string to print depending if &#39;boolValue&#39; is evaluated as true or false
        const char* whichString = boolValue ? &quot;true&quot; : &quot;false&quot;;
        
        // Compute the length of the string we selected
        size_t len = strlen(whichString);
        
        memcpy(destBuffer, whichString, len);
    }
    
    int main()
    {
        // Locally construct an instance of our struct here on the stack. The bool member uninitializedBool is uninitialized.
        FStruct structInstance;
        
        // Output &quot;true&quot; or &quot;false&quot; to stdout
        Serialize(structInstance.uninitializedBool);
        return 0;
    }

The problem arises because of the optimizer: It was clever enough to deduce that the strings &quot;true&quot; and &quot;false&quot; only differs in length by 1. So instead of really calculating the length, it uses the value of the bool itself, which *should* technically be either 0 or 1, and goes like this:

    const size_t len = strlen(whichString); // original code
    const size_t len = 5 - boolValue;       // clang clever optimization

While this is &quot;clever&quot;, so to speak, my question is: **Does the C++ standard allow a compiler to assume a bool can only have an internal numerical representation of &#39;0&#39; or &#39;1&#39; and use it in such a way?**

Or is this a case of implementation-defined, in which case the implementation assumed that all its bools will only ever contain 0 or 1, and any other value is undefined behaviour territory?

Content Type	Original Author	Original Content on Stackoverflow
Question	Martin L.	View Question on Stackoverflow
Solution 1 - Android	IgorGanapolsky	View Answer on Stackoverflow

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