Audio: port Context away from std::vector and std::string.

Basically mirrors what 95b3f8578d did for
GL::Context.

doc/changelog.dox

@@ -1991,6 +1991,17 @@ See also:
         @relativeref{Corrade,Containers::Array} /
         @relativeref{Corrade,Containers::ArrayView} of them, instead of a
         @ref std::string and a @ref std::vector.
+    -   @ref Audio::Context::deviceSpecifierStrings(),
+        @relativeref{Audio::Context,hrtfSpecifierString()},
+        @relativeref{Audio::Context,deviceSpecifierString()},
+        @relativeref{Audio::Context,vendorString()},
+        @relativeref{Audio::Context,rendererString()},
+        @relativeref{Audio::Context,versionString()},
+        @relativeref{Audio::Context,extensionStrings()} now return
+        @relativeref{Corrade,Containers::StringView} or a
+        @relativeref{Corrade,Containers::Array} /
+        @relativeref{Corrade,Containers::ArrayView} of them, instead of a
+        @ref std::string and a @ref std::vector.
     -   All @ref GL::Buffer::label() "label()" and
         @ref GL::Buffer::setLabel() "setLabel()" APIs now work with a
         @relativeref{Corrade,Containers::StringView} /

src/Magnum/Audio/Context.cpp

@@ -29,11 +29,10 @@
 #include "Context.h"
 
 #include <algorithm> /* std::lower_bound() */
+#include <Corrade/Containers/GrowableArray.h>
 #include <Corrade/Utility/Arguments.h>
 #include <Corrade/Utility/Assert.h>
 #include <Corrade/Utility/Debug.h>
-#include <Corrade/Utility/DebugStl.h>
-#include <Corrade/Utility/String.h>
 
 #include "Magnum/Audio/Extensions.h"
 
@@ -61,6 +60,16 @@ constexpr Extension ExtensionList[]{
     #undef _entension
 };
 
+const Extension* findExtension(const Containers::StringView extension) {
+    const auto found = std::lower_bound(std::begin(ExtensionList), std::end(ExtensionList), extension, [](const Extension& a, const Containers::StringView& b) {
+        return a.string() < b;
+    });
+    if(found != std::end(ExtensionList) && found->string() == extension)
+        return found;
+
+    return {};
+}
+
 }
 
 Containers::ArrayView<const Extension> Extension::extensions() {
@@ -108,11 +117,11 @@ const char* alcErrorString(const ALenum error) {
 
 }
 
-std::vector<std::string> Context::deviceSpecifierStrings() {
-    std::vector<std::string> list;
+Containers::Array<Containers::StringView> Context::deviceSpecifierStrings() {
+    Containers::Array<Containers::StringView> list;
     const char* device = alcGetString(nullptr, ALC_DEVICE_SPECIFIER);
     while(*device) {
-        list.emplace_back(device);
+        arrayAppend(list, {device, Containers::StringViewFlag::Global});
         device += list.back().size() + 1;
     }
 
@@ -197,9 +206,17 @@ Context::Context(NoCreateT, const Int argc, const char* const* const argv) noexc
     /* Decide how to display initialization log */
     _displayInitializationLog = !(args.value("log") == "quiet" || args.value("log") == "QUIET");
 
-    /* Disable extensions */
-    for(auto&& extension: Utility::String::splitWithoutEmptyParts(args.value("disable-extensions")))
-        _disabledExtensionStrings.push_back(extension);
+    /* Disable extensions. Here we search for them among the known extensions
+       and store the Extension objects instead, which avoids the string copying
+       and another binary search in tryCreate(). */
+    const Containers::StringView disabledExtensions = args.value<Containers::StringView>("disable-extensions");
+    if(!disabledExtensions.isEmpty()) {
+        const Containers::Array<Containers::StringView> split = disabledExtensions.splitOnWhitespaceWithoutEmptyParts();
+        arrayReserve(_disabledExtensions, split.size());
+        for(const Containers::StringView extension: split)
+            if(const Extension* found = findExtension(extension))
+                arrayAppend(_disabledExtensions, *found);
+    }
 }
 
 void Context::create(const Configuration& configuration) {
@@ -211,7 +228,7 @@ bool Context::tryCreate(const Configuration& configuration) {
     CORRADE_ASSERT(!currentContext, "Audio::Context: context already created", false);
 
     /* Open the device */
-    const ALCchar* const deviceSpecifier = configuration.deviceSpecifier().empty() ? alcGetString(nullptr, ALC_DEFAULT_DEVICE_SPECIFIER) : configuration.deviceSpecifier().data();
+    const ALCchar* const deviceSpecifier = configuration.deviceSpecifier().isEmpty() ? alcGetString(nullptr, ALC_DEFAULT_DEVICE_SPECIFIER) : configuration.deviceSpecifier().data();
     if(!(_device = alcOpenDevice(deviceSpecifier))) {
         Error() << "Audio::Context: cannot open sound device" << deviceSpecifier;
         return false;
@@ -270,11 +287,10 @@ bool Context::tryCreate(const Configuration& configuration) {
     currentContext = this;
 
     /* Check for presence of extensions */
-    const std::vector<std::string> extensions = extensionStrings();
-    for(const std::string& extension: extensions) {
-        const auto found = std::lower_bound(std::begin(ExtensionList), std::end(ExtensionList), extension, [](const Extension& a, const std::string& b) { return a.string() < b; });
-        if(found != std::end(ExtensionList) && found->string() == extension) {
-            _supportedExtensions.push_back(*found);
+    const Containers::Array<Containers::StringView> extensions = extensionStrings();
+    for(const Containers::StringView extension: extensions) {
+        if(const Extension* found = findExtension(extension)) {
+            arrayAppend(_supportedExtensions, *found);
             _extensionStatus.set(found->index(), true);
         }
     }
@@ -286,33 +302,15 @@ bool Context::tryCreate(const Configuration& configuration) {
     Debug{output} << "OpenAL version:" << versionString();
 
     /* Disable extensions as requested by the user */
-    if(!_disabledExtensionStrings.empty()) {
-        bool headerPrinted = false;
+    if(!_disabledExtensions.isEmpty()) {
+        Debug{output} << "Disabling extensions:";
 
         /* Disable extensions that are known and supported and print a message
            for each */
-        for(auto&& extension: _disabledExtensionStrings) {
-            const auto found = std::lower_bound(std::begin(ExtensionList), std::end(ExtensionList), extension, [](const Extension& a, const std::string& b) { return a.string() < b; });
-            /* No error message here because some of the extensions could be
-               from Vulkan or OpenGL. That also means we print the header only
-               when we actually have something to say */
-            if(found == std::end(ExtensionList) || found->string() != extension)
-                continue;
-
-            /* If the extension isn't supported in the first place, don't do
-               anything. If it is, set its status as unsupported but flip the
-               corresponding bit in the disabled bitmap so we know it is
-               supported and only got disabled */
-            if(!_extensionStatus[found->index()])
-                continue;
-            _extensionStatus.set(found->index(), false);
-            _disabledExtensions.set(found->index(), true);
-
-            if(!headerPrinted) {
-                Debug{output} << "Disabling extensions:";
-                headerPrinted = true;
-            }
-            Debug{output} << "   " << extension;
+        for(const Extension& extension: _disabledExtensions) {
+            _extensionStatus.set(extension.index(), false);
+            _extensionDisabledStatus.set(extension.index(), true);
+            Debug{output} << "   " << extension.string();
         }
     }
 
@@ -335,15 +333,12 @@ Context::~Context() {
         currentContext = nullptr;
 }
 
-std::vector<std::string> Context::extensionStrings() const {
-    std::vector<std::string> extensions;
-
-    /* Don't crash when alGetString() returns nullptr */
-    extensions = Utility::String::splitWithoutEmptyParts(Utility::String::fromArray(reinterpret_cast<const char*>(alGetString(AL_EXTENSIONS))), ' ');
+Containers::Array<Containers::StringView> Context::extensionStrings() const {
+    Containers::Array<Containers::StringView> extensions = Containers::StringView{reinterpret_cast<const char*>(alGetString(AL_EXTENSIONS)), Containers::StringViewFlag::Global}.splitWithoutEmptyParts(' ');
 
-    /* Add ALC extensions as well */
-    auto splitAlcExts = Utility::String::splitWithoutEmptyParts(Utility::String::fromArray(reinterpret_cast<const char*>(alcGetString(_device, ALC_EXTENSIONS))), ' ');
-    extensions.insert(extensions.end(), splitAlcExts.begin(), splitAlcExts.end());
+    /* Add ALC extensions as well. This reallocates the above array but that's
+       fine, it's not a hot code path. */
+    arrayAppend(extensions, Containers::StringView{reinterpret_cast<const char*>(alcGetString(_device, ALC_EXTENSIONS)), Containers::StringViewFlag::Global}.splitWithoutEmptyParts(' '));
 
     return extensions;
 }
@@ -369,9 +364,9 @@ Context::HrtfStatus Context::hrtfStatus() const {
     return Context::HrtfStatus(status);
 }
 
-std::string Context::hrtfSpecifierString() const {
+Containers::StringView Context::hrtfSpecifierString() const {
     /* Returns a string on ALC_SOFT_HRTF, nullptr on ALC_SOFTX_HRTF */
-    return Utility::String::fromArray(alcGetString(_device, ALC_HRTF_SPECIFIER_SOFT));
+    return {alcGetString(_device, ALC_HRTF_SPECIFIER_SOFT), Containers::StringViewFlag::Global};
 }
 
 Int Context::monoSourceCount() const {
@@ -392,33 +387,20 @@ Int Context::refreshRate() const {
     return count;
 }
 
-std::string Context::deviceSpecifierString() const {
-    return alcGetString(_device, ALC_DEVICE_SPECIFIER);
+Containers::StringView Context::deviceSpecifierString() const {
+    return {alcGetString(_device, ALC_DEVICE_SPECIFIER), Containers::StringViewFlag::Global};
 }
 
-std::string Context::vendorString() const {
-    return alGetString(AL_VENDOR);
+Containers::StringView Context::vendorString() const {
+    return {alGetString(AL_VENDOR), Containers::StringViewFlag::Global};
 }
 
-std::string Context::rendererString() const {
-    return alGetString(AL_RENDERER);
-}
-
-std::string Context::versionString() const {
-    return alGetString(AL_VERSION);
-}
-
-Context::Configuration::Configuration() = default;
-Context::Configuration::~Configuration() = default;
-
-Context::Configuration& Context::Configuration::setDeviceSpecifier(const std::string& specifier) {
-    _deviceSpecifier = specifier;
-    return *this;
+Containers::StringView Context::rendererString() const {
+    return {alGetString(AL_RENDERER), Containers::StringViewFlag::Global};
 }
 
-Context::Configuration& Context::Configuration::setDeviceSpecifier(std::string&& specifier) {
-    _deviceSpecifier = Utility::move(specifier);
-    return *this;
+Containers::StringView Context::versionString() const {
+    return {alGetString(AL_VERSION), Containers::StringViewFlag::Global};
 }
 
 }}

src/Magnum/Audio/Context.h

@@ -33,9 +33,9 @@
  */
 
 #include <cstdlib> /* std::abort() in MAGNUM_ASSERT_AUDIO_EXTENSION_SUPPORTED() */
-#include <string>
-#include <vector>
+#include <Corrade/Containers/Array.h>
 #include <Corrade/Containers/EnumSet.h>
+#include <Corrade/Containers/String.h> /** @todo PIMPL Configuration instead? */
 #include <Corrade/Utility/Debug.h>
 
 #include "Magnum/Magnum.h"
@@ -50,6 +50,12 @@
 #include <alc.h>
 #include "MagnumExternal/OpenAL/extensions.h"
 
+#ifdef MAGNUM_BUILD_DEPRECATED
+/* For return types of Context::versionString() etc., which used to be a
+   std::string. Not ideal for the return types, but at least something. */
+#include <Corrade/Containers/StringStl.h>
+#endif
+
 namespace Magnum { namespace Audio {
 
 namespace Implementation {
@@ -180,7 +186,7 @@ class MAGNUM_AUDIO_EXPORT Context {
          * @see @ref deviceSpecifierString(), @ref Configuration::setDeviceSpecifier()
          *      @fn_alc{GetString} with @def_alc_keyword{DEVICE_SPECIFIER}
          */
-        static std::vector<std::string> deviceSpecifierStrings();
+        static Containers::Array<Containers::StringView> deviceSpecifierStrings();
 
         /**
          * @brief Whether there is any current context
@@ -306,11 +312,14 @@ class MAGNUM_AUDIO_EXPORT Context {
          * @brief HRTF specifier
          *
          * Name of the HRTF being used. The result is *not* cached, repeated
-         * queries will result in repeated OpenAL calls.
+         * queries will result in repeated OpenAL calls. The returned view is
+         * always @relativeref{Corrade::Containers::StringViewFlag,Global}, and
+         * if non-empty it's also
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated}.
          * @see @fn_al{GetString} with @def_alc_keyword{HRTF_SPECIFIER_SOFT}
          * @requires_al_extension @alc_extension{SOFT,HRTF}
          */
-        std::string hrtfSpecifierString() const;
+        Containers::StringView hrtfSpecifierString() const;
 
         /**
          * @brief Count of supported mono sources
@@ -349,40 +358,48 @@ class MAGNUM_AUDIO_EXPORT Context {
          * @brief Device specifier string
          *
          * The result is *not* cached, repeated queries will result in repeated
-         * OpenAL calls.
+         * OpenAL calls. The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * @relativeref{Corrade::Containers::StringViewFlag,Global}.
          * @see @ref deviceSpecifierStrings(), @ref vendorString(), @ref rendererString(),
          *      @fn_al{GetString} with @def_alc_keyword{DEVICE_SPECIFIER}
          */
-        std::string deviceSpecifierString() const;
+        Containers::StringView deviceSpecifierString() const;
 
         /**
          * @brief Vendor string
          *
          * The result is *not* cached, repeated queries will result in repeated
-         * OpenAL calls.
+         * OpenAL calls. The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * @relativeref{Corrade::Containers::StringViewFlag,Global}.
          * @see @ref deviceSpecifierString(), @ref rendererString(),
          *      @fn_al{GetString} with @def_al_keyword{VENDOR}
          */
-        std::string vendorString() const;
+        Containers::StringView vendorString() const;
 
         /**
          * @brief Renderer string
          *
          * The result is *not* cached, repeated queries will result in repeated
-         * OpenAL calls.
+         * OpenAL calls. The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * @relativeref{Corrade::Containers::StringViewFlag,Global}.
          * @see @ref deviceSpecifierString(), @ref vendorString(),
          *      @fn_al{GetString} with @def_al_keyword{RENDERER}
          */
-        std::string rendererString() const;
+        Containers::StringView rendererString() const;
 
         /**
          * @brief Version string
          *
          * The result is *not* cached, repeated queries will result in repeated
-         * OpenAL calls.
+         * OpenAL calls. The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * @relativeref{Corrade::Containers::StringViewFlag,Global}.
          * @see @fn_al{GetString} with @def_al_keyword{VERSION}
          */
-        std::string versionString() const;
+        Containers::StringView versionString() const;
 
         /**
          * @brief Extension strings
@@ -391,12 +408,15 @@ class MAGNUM_AUDIO_EXPORT Context {
          * OpenAL calls. Note that this function returns list of all extensions
          * reported by the driver (even those not supported by Magnum), see
          * @ref supportedExtensions(), @ref Extension::extensions() or
-         * @ref isExtensionSupported() for alternatives.
+         * @ref isExtensionSupported() for alternatives. The returned views are
+         * always @relativeref{Corrade::Containers::StringViewFlag,Global}, but
+         * as the extensions are split from a space-separated list only the
+         * last one is guaranteed to be null-terminated.
          * @see @fn_al{Get} with @def_al_keyword{NUM_EXTENSIONS},
          *      @fn_al{GetString} with @def_al_keyword{EXTENSIONS},
          *      @fn_alc{GetString} with @def_alc_keyword{EXTENSIONS}
          */
-        std::vector<std::string> extensionStrings() const;
+        Containers::Array<Containers::StringView> extensionStrings() const;
 
         /**
          * @brief Supported extensions
@@ -405,7 +425,7 @@ class MAGNUM_AUDIO_EXPORT Context {
          * the current.
          * @see @ref isExtensionSupported(), @ref Extension::extensions()
          */
-        const std::vector<Extension>& supportedExtensions() const {
+        Containers::ArrayView<const Extension> supportedExtensions() const {
             return _supportedExtensions;
         }
 
@@ -446,7 +466,7 @@ class MAGNUM_AUDIO_EXPORT Context {
          * if they are advertised as being supported by the driver.
          */
         template<class T> bool isExtensionDisabled() const {
-            return _disabledExtensions[T::Index];
+            return _extensionDisabledStatus[T::Index];
         }
 
         /**
@@ -457,7 +477,7 @@ class MAGNUM_AUDIO_EXPORT Context {
          * as it does most operations in compile time.
          */
         bool isExtensionDisabled(const Extension& extension) const {
-            return _disabledExtensions[extension.index()];
+            return _extensionDisabledStatus[extension.index()];
         }
 
     private:
@@ -467,9 +487,9 @@ class MAGNUM_AUDIO_EXPORT Context {
         ALCcontext* _context;
 
         Math::BitVector<Implementation::ExtensionCount> _extensionStatus;
-        Math::BitVector<Implementation::ExtensionCount> _disabledExtensions;
-        std::vector<Extension> _supportedExtensions;
-        std::vector<std::string> _disabledExtensionStrings;
+        Math::BitVector<Implementation::ExtensionCount> _extensionDisabledStatus;
+        Containers::Array<Extension> _supportedExtensions;
+        Containers::Array<Extension> _disabledExtensions;
 };
 
 /**
@@ -477,7 +497,7 @@ class MAGNUM_AUDIO_EXPORT Context {
 
 @see @ref Context()
 */
-class MAGNUM_AUDIO_EXPORT Context::Configuration {
+class Context::Configuration {
     public:
         /**
          * @brief HRTF configuration
@@ -491,22 +511,33 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
             Disabled = 2    /**< Disabled */
         };
 
-        explicit Configuration();
-        ~Configuration();
-
-        /** @brief Device specifier */
-        const std::string& deviceSpecifier() const { return _deviceSpecifier; }
+        /**
+         * @brief Device specifier
+         *
+         * The returned string view is
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * is valid until the next call to @ref setDeviceSpecifier().
+         */
+        Containers::StringView deviceSpecifier() const { return _deviceSpecifier; }
 
         /**
          * @brief Set device specifier
          * @return Reference to self (for method chaining)
          *
-         * If set to empty string (the default), default device specifier is
+         * If set to an empty string (the default), default device specifier is
          * used.
+         *
+         * @note The function makes a copy of the view if it's not not global
+         *      or null-terminated, use the
+         *      @link Corrade::Containers::Literals::StringLiterals::operator""_s() Containers::Literals::operator""_s() @endlink
+         *      literal to prevent that where possible.
+         *
          * @see @ref Context::deviceSpecifierStrings()
          */
-        Configuration& setDeviceSpecifier(const std::string& specifier);
-        Configuration& setDeviceSpecifier(std::string&& specifier); /**< @overload */
+        Configuration& setDeviceSpecifier(Containers::StringView specifier) {
+            _deviceSpecifier = Containers::String::nullTerminatedGlobalView(specifier);
+            return *this;
+        }
 
         /** @brief Sampling rate in Hz */
         Int frequency() const { return _frequency; }
@@ -592,7 +623,7 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
         }
 
     private:
-        std::string _deviceSpecifier;
+        Containers::String _deviceSpecifier;
 
         Int _frequency{-1};
         Hrtf _hrtf{};

src/Magnum/Audio/Test/ContextALTest.cpp

@@ -54,6 +54,8 @@ struct ContextALTest: TestSuite::Tester {
     void isExtensionSupported();
     void isExtensionUnsupported();
     void isExtensionDisabled();
+
+    void stringFlags();
 };
 
 const struct {
@@ -82,13 +84,15 @@ ContextALTest::ContextALTest():
               &ContextALTest::extensionsString,
               &ContextALTest::isExtensionSupported,
               &ContextALTest::isExtensionUnsupported,
-              &ContextALTest::isExtensionDisabled});
+              &ContextALTest::isExtensionDisabled,
+
+              &ContextALTest::stringFlags});
 }
 
 void ContextALTest::deviceSpecifierStrings() {
     /* Just verify that it produces something reasonable without crashing or
        entering an infinite loop */
-    CORRADE_VERIFY(!Context::deviceSpecifierStrings().empty());
+    CORRADE_VERIFY(!Context::deviceSpecifierStrings().isEmpty());
 }
 
 void ContextALTest::constructDefault() {
@@ -155,10 +159,10 @@ void ContextALTest::constructConfiguration() {
             /* HRTF gets enabled only if the extension is supported */
             if(context.isExtensionSupported<Extensions::ALC::SOFT::HRTF>()) {
                 CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Enabled);
-                CORRADE_VERIFY(!context.hrtfSpecifierString().empty());
+                CORRADE_VERIFY(!context.hrtfSpecifierString().isEmpty());
             } else if(context.isExtensionSupported<Extensions::ALC::SOFTX::HRTF>()) {
                 CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Enabled);
-                CORRADE_VERIFY(context.hrtfSpecifierString().empty());
+                CORRADE_VERIFY(context.hrtfSpecifierString().isEmpty());
             } else {
                 CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Disabled);
             }
@@ -232,9 +236,7 @@ void ContextALTest::ignoreUnrelatedOptions() {
 void ContextALTest::extensionsString() {
     Context context;
 
-    std::vector<std::string> extensions = context.extensionStrings();
-
-    CORRADE_VERIFY(!extensions.empty());
+    CORRADE_VERIFY(!context.extensionStrings().isEmpty());
 }
 
 void ContextALTest::isExtensionSupported() {
@@ -278,6 +280,43 @@ void ContextALTest::isExtensionDisabled() {
     CORRADE_VERIFY(context.isExtensionDisabled(e));
 }
 
+void ContextALTest::stringFlags() {
+    Containers::Array<Containers::StringView> deviceSpecifierStrings = Context::deviceSpecifierStrings();
+    CORRADE_VERIFY(!deviceSpecifierStrings.isEmpty());
+    for(Containers::StringView specifier: deviceSpecifierStrings) {
+        CORRADE_VERIFY(!specifier.isEmpty());
+        CORRADE_COMPARE(specifier.flags(), Containers::StringViewFlag::Global|Containers::StringViewFlag::NullTerminated);
+    }
+
+    Context context;
+
+    /* HRTF specifier string might be null, in which case it's *not*
+       null-terminated obviously */
+    CORRADE_COMPARE(context.hrtfSpecifierString().flags(), Containers::StringViewFlag::Global|(context.hrtfSpecifierString().data() ? Containers::StringViewFlag::NullTerminated : Containers::StringViewFlags{}));
+
+    CORRADE_VERIFY(!context.deviceSpecifierString().isEmpty());
+    CORRADE_COMPARE(context.deviceSpecifierString().flags(), Containers::StringViewFlag::Global|Containers::StringViewFlag::NullTerminated);
+
+    CORRADE_VERIFY(!context.vendorString().isEmpty());
+    CORRADE_COMPARE(context.vendorString().flags(), Containers::StringViewFlag::Global|Containers::StringViewFlag::NullTerminated);
+
+    CORRADE_VERIFY(!context.rendererString().isEmpty());
+    CORRADE_COMPARE(context.rendererString().flags(), Containers::StringViewFlag::Global|Containers::StringViewFlag::NullTerminated);
+
+    CORRADE_VERIFY(!context.versionString().isEmpty());
+    CORRADE_COMPARE(context.versionString().flags(), Containers::StringViewFlag::Global|Containers::StringViewFlag::NullTerminated);
+
+    for(Containers::StringView extension: context.extensionStrings()) {
+        CORRADE_ITERATION(extension);
+        CORRADE_VERIFY(!extension.isEmpty());
+
+        /* The extensions are split from a long string and thus aren't all
+           null-terminated, only the last one */
+        CORRADE_COMPARE_AS(extension.flags(), Containers::StringViewFlag::Global,
+            TestSuite::Compare::GreaterOrEqual);
+    }
+}
+
 }}}}
 
 CORRADE_TEST_MAIN(Magnum::Audio::Test::ContextALTest)