String concatenation with QStringBuilder - Q

In Qt 4.6 we introduced a kind of hidden class in Qt: QStringBuilder And it was improved in Qt 4.8 by adding support for QByteArray as well. Because it is source incompatible (see below), you need to explicitly enable it. The way to enable it with Qt 4.7 is described in the 4.7 QString documentatio QStringBuilder (const A &a_, const B &b_) operator ConvertTo const : int: size const : QByteArray: toLatin1 cons The additional mallocs can be avoided if the length of the final QString is known in advance. Qt 4.6 introduces an internal class called QStringBuilder that reserves memory for a concatenation chain in a single shot. It does so by having each of the + operations above return a different class (not QString anymore) QStringBuilder. We already discussed the usage of expression templates for the optimization of string construction. Qt provides an internal template class called QStringBuilder, which provides the expression template base optimization for concatenations of QString instances. This class isn't meant to be instantiated directly, but will be automatically invoked when its overloaded % operator is. QString provides many functions for converting numbers into strings and strings into numbers. See the arg () functions, the setNum () functions, the number () static functions, and the toInt (), toDouble (), and similar functions. To get an upper- or lowercase version of a string use toUpper () or toLower ()

QStringBuilder - BlackBerry Nativ

QStringBuilder (const QByteArray &a_, const QByteArray &b_) operator QByteArray cons QStringBuilder was created to optimize concatenation expressions, and that optimization is achieved by eliminating the need for temporaries, and calculating the total size of the concatenated string and allocating it all at once (obviously, this can only be done at the end of the expression) Instead of returning a QString the operator+ will return an instance of a hidden class template called QStringBuilder. The QStringBuilderclass template is just a dummy type that holds references to the arguments passed to the operator+. Basically, a more complex version of the following

A QString can be rendered on the screen or to a printer, provided there is a font to display the characters that the QString holds. All user-visible strings in Qt are stored in QString. Internally, QString stores the string using the UTF-16 encoding. Each of the 2 bytes of UTF-16 is represented using a QChar QStringBuilder wurde erstellt, um Verkettungsausdrücke zu optimieren, und diese Optimierung wird erreicht, indem die Notwendigkeit für Provisorien entfällt und die Gesamtgröße der verketteten Zeichenfolge berechnet und alle auf einmal zugewiesen werden (natürlich kann dies nur am Ende der Ausdruck) c++ - qstringbuilder - qstringliteral Konvertieren von QString in char* (2) Mögliche Duplikate: Umwandlung von QString in Cha QStringBuilder(const QString &a_, const QString &b_) : a, b {} 144: QStringBuilder(const QStringBuilder &other) : a(other.a), b(other.b) {} 145: 146: operator QString() const: 147 { QString r; r += b; return r; } 148: 149: const QString &a; 150: const QString &b; 151: 152: private: 153: QStringBuilder &operator=(const QStringBuilder &) Q_DECL_EQ_DELETE; 154}; 155: 156: template <> 15

Using QString Effectively - Qt Wik

QStringBuilder - Hands-On High Performance Programming

  1. QStringBuilder uses expression templates and reimplements the '%' operator so that when you use '%' for string concatenation instead of '+', multiple substring concatenations will be postponed until the final result is about to be assigned to a QString. At this point, the amount of memory required for the final result is known. The memory allocator is then called once to get the required space.
  2. QStringBuilder uses expression templates to collect the individual-58: chunks, compute the total size, allocate the required amount of-59: memory for the final string object, and copy the chunks into the-60: allocated memory.-61-62: The QStringBuilder class is not to be used explicitly in user-63: code. Instances of the class are created as.

c++ - number - qstringbuilder Umwandlung von QString in Char* (5) Ich habe versucht, einen QString mit den folgenden Methoden in Char * Typ zu konvertieren, aber sie scheinen nicht zu funktionieren Also I was just wondering why QStringBuilder provides an operator%, but doesn't provide any operator%=? The latter operator would be just as useful of the former. So one doesn't have to write someQString = someQString % restOfData instead of the neat form someQString %= restOfData. Another question is why QString doesn't provide a constructor and operator= accepting QStringBuilder. With it. \class QStringBuilder-48 \inmodule QtCore-49 \internal-50 \reentrant-51 \since 4.6-52-53 \brief The QStringBuilder class is a template class that provides a facility to build up QStrings from smaller chunks.-54-55 \ingroup tools-56 \ingroup shared-57 \ingroup string-processing-58-59-60: To build a QString by multiple concatenations, QString::operator+() -61: is typically used. This causes \e{n. Now that we have developed the technique, we very strongly expect it to be used in Qt 6.0 for QStringBuilder, too. By Qt 6.0, we expect QStringTokenizer to also handle the then-available QUtf8StringView as haystack and needle, as well as QRegularExpression and std:: boyer_moore_searcher and std::boyer_moore_horspool_searcher as needles. We might also re-implement it as a C++20 coroutine on.

QStringView Past, Present, Future Marc Mutz, Senior Software Engineer at KDA \c{QStringBuilder} computes the amount of memory required for the: final string. Additional efficiency is gained by inlining and reduced reference: counting (the QString created from a \c{QStringBuilder} typically: has a ref count of 1, whereas QString::append() needs an extra: test). There are three ways you can access this improved method of.

QStringBuilder QByteArray, QByteArray - BlackBerry Nativ

  1. However the fact that enabling QStringBuilder here caused a crash in previously working code without even emitting a warning means that I will now avoid using it elsewhere unless I can guarantee that this will not happen again. Since in this case RVO could prevent any copying from occurring I don't think the usual technique of disabling copying of the object would work. Is there a way to.
  2. Explanation for checker auto-unexpected-qstringbuilder (level1) auto-unexpected-qstringbuilder. Finds places where auto is deduced to be QStringBuilder instead of QString, which introduces crashes. Also warns for lambdas returning QStringBuilder. Exampl
  3. main.cpp: warning: auto deduced to be QStringBuilder instead of QString. Possible crash. [-Wclazy-auto-unexpected-qstringbuilder] Possible crash. [-Wclazy-auto-unexpected-qstringbuilder
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  5. Is it possible to compile Qt 4.8.7? I have passed the following steps: 1. build all images for LS1043ARDB, including toolchains. 2. create device spec for LS1043ARDB linux-ls1043a-arm-g++ for building Qt qmake.conf # # qmake configuration for building with arm-linux-gnueabi-g++ # include(../../c..
  6. QStringBuilder. QStringBuilder uses expression templates and reimplements the '%' operator so that when you use '%' for string concatenation instead of '+', multiple substring concatenations will be postponed until the final result is about to be assigned to a QString. At this point, the amount of memory required for the final result is known. QStringBuilder. #include <QtCore/QStringBuilder.

c++ - Qt string builder in for loop - Stack Overflo

  1. Removing networking features from the Qt build. GitHub Gist: instantly share code, notes, and snippets
  2. Introduction. QxOrm is a C++ library designed to provide Object Relational Mapping (ORM) feature to C++ users. With a simple C++ setting function by class (like Hibernate XML mapping file), you will have access to the following features:. Persistence: Communication with a lot of databases (with 1-1, 1-n, n-1 and n-n relationships); Serialization: Binary and XML forma
  3. Just a theory: sometimes compile errors can happen when some of the dependencies aren't fully in check. For example: you upgraded from FreeBSD 10.3 to 11.0 but haven't recompiled all your ports
  4. With QT_USE_QSTRINGBUILDER being enabled, code best is checked with clazy -checks=auto-unexpected-qstringbuilder for these traps now enabled. Diff Detail. Repository R6 KActivities Lint . Automatic diff as part of commit; lint not applicable. Unit . Automatic diff as part of commit; unit tests not applicable..
  5. counting (the QString created from a \c{QStringBuilder} typically: has a ref count of 1, whereas QString::append() needs an extra: test). There are three ways you can access this improved method of string: construction. The straightforward way is to include \c{QStringBuilder} wherever you want to use it, and use th
  6. #include <qstringbuilder.h> Class Description. template<typename T> struct QtStringBuilder::ConvertToTypeHelper< T, QString > Definition at line 387 of file qstringbuilder.h. Public Types: typedef QString ConvertTo Member Typedef Documentation. typedef QString ConvertTo: Definition at line 388 of file qstringbuilder.h. The documentation for this struct was generated from the following file.
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Tuy nhiên tôi không hiểu làm thế nào tôi có thể viết nó để sử dụng QStringBuilder như ở đây tôi đang làm một bài tập, thay vào đó là QStringBuilder đòi hỏi tôi phải sử dụng toán tử% và chỉ thực hiện một bài tập theo tài liệu The tool is safe for use with QStrings and the QStringBuilder expression template - it won't replace a QString which triggers a conversion from QStringBuilder with a use of auto. It only ports declarations for which the type of the left hand side matches the type of the right hand side without conversion. It can even issue warnings for locations where the tool is not able to introduce use. Definition at line 70 of file qstringbuilder.h. 71 : m_size(N - 1), m_data(str) {} Member Function Documentation. int size const: inline: Definition at line 66 of file qstringbuilder.h. 66 { return m_size; } const char* data const: inline: Definition at line 67 of file qstringbuilder.h. 67 { return m_data; } The documentation for this class was generated from the following file: QtCore. QCustomPlot is a Qt C++ widget for plotting. This plotting library focuses on making good looking, publication quality 2D plots, graphs and charts, as well as offering high performance for realtime visualization

ошибка: no match for 'operator<<' in 'output << operator+ [with A = QStringBuilder<QStringBuilder<QString, char [4]>, QString>, B = char [2], typename. The power of QStringBuilder only sets in if more than two strings are concatenated before picking up the result as QString again (e.g. when assigning to a QString variable). There are some code parts where a lot of concatenating is done, but not in one expression, instead assigning the intermediate result to a QString var again and again, thus preventing the advantage of QStringBuilder. There. Qt does not expose the standard library in its ABI: ☺ Qt compiled against one implementation is binary compatible with applications compiled against another implementation

Efficient QString concatenation with C++17 fold expression

Well, since the introduction of QStringBuilder in Qt 4.7 we have expression templates for a very common use case, string concatenations. And if your code is somewhere in KDE Git, it's very likely Laurent enabled the use of QStringBuilder for you already. So, we are not talking about exotic theory here, but about tools you are using every day. Info. Day: 2013-07-14 Start time: 15:30 Duration. QStringBuilder - Size info is probably lost for most compilers - Still out-of-line QString dtors cluttering the code Avoid. Strongly prefer QLatin1String. - Option for non-latin1-string literals, though Couple observations: - I am doing nothing different from what I'm doing while building Qt 5.5.1 - -stdlib=libc++ appear to be missing only from CXXFLAGS in the Makefiles unde enum SectionFlag { SectionDefault, SectionSkipEmpty, SectionIncludeLeadingSep, SectionIncludeTrailingSep, SectionCaseInsensitiveSeps }; class SectionFlag

Using QString effectively

QString - Qt Wik

Qt 4.6 introduces an internal class called QStringBuilder that reserves memory for a concatenation chain in a single shot. It does so by having each of the + operations above return a different class (not QString). This class keeps track of the string's that are being appended and the required memory at each step. At the final step, where the concatenation operation gets converted into. GCC Bugzilla - Bug 60818 ICE in validate_condition_mode on powerpc*-linux-gnu* Last modified: 2017-11-01 22:48:15 UT Add .gitlab-ci.yml 8 jobs for gitlab-ci in 97 minutes and 50 seconds gitlab-ci in 97 minutes and 50 second

Hi Andreas, thank you for the patch. Looking at it, I havenoticed an Qt issue: In Qt 5, there is typedef QLatin1String QLatin1Literal; However, I cannot find the original template constructor sparhawk wrote:I'm not sure if this is related, but when I boot, I get this message, asking for root permission.When I hover over the link, it says Click to edit org.kde.baloo.filewatch.raiselimit. I've only noticed this in the last week or so, probably since the upgrade from baloo 5.9.2-1 -> 5.13.0-2 on 19 August Using Arch Linux, Qt 5.5, gcc 5.2 and speedcrunch from git master, it fails to build. ``` #!bash qmake-qt5 speedcrunch.pro make ``` ``` #!c++ g++ -c -pipe -O2 -march. imagemetadata.h (mythtv-30.0): imagemetadata.h (mythtv-31.0) skipping to change at line 12 skipping to change at line 12 //! \brief Handles Exif/FFMpeg metadata tags for image

qTox: src/widget/style

Oh no! Some styles failed to load. Please try reloading this page Help Create Join Login. Open Source Software. Accounting; CRM; Business Intelligenc Project MESSAGE: Building Musique 1.10.1 Project MESSAGE: Qt 5.15.2 in /usr Project MESSAGE: Building for release Project MESSAGE: QT: core gui network sql widgets dbus qml dbus Project MESSAGE: CONFIG: lex yacc debug exceptions depend_includepath testcase_targets import_plugins import_qpa_plugin file_copies qmake_use qt warn_on release link_prl incremental shared shared release linux unix. inet_aton() converts the Internet host address cp from the IPv4 numbers-and-dots notation into binary form (in network byte order) and stores it in the structure that inp points to.inet_aton() returns nonzero if the address is valid, zero if not.The address supplied in cp can have one of the following forms: a.b.c.d. Each of the four numeric parts specifies a byte of the address; the bytes are.

main.log (1019.7 KB) - added by bK4gYuRo 5 years ago. build log of qt4-mac patch-src_network_ssl_qsslsocket_openssl.diff (5.2 KB) - added by kylesch@ 4 years ago. patch allowing qt4-mac to build against libressl by wrapping SSLv3_* function calls in macro checks using '#ifndef OPENSSL_NO_SSLV3 How could I disable in a source filea Warning 673: Warning #673: the initial sequence of preprocessing directives is not compatible with those of precompiled header file Debug\\\\.pchi The same question is for Intel C++ compilerremarks... Best regards, Serge FWIW, altering QStringBuilder.h to be this works, but I'd like to not have to modify the Qt source code: typedef QConcatenable<QStringBuilder<A, B> > Concatenable; // typedef typename Concatenable::ConvertTo ConvertTo; public: operator typename Concatenable::ConvertTo() const { return convertTo<typename Concatenable::ConvertTo>(); } -Josh. Re: cpptoxml crashes due to infinite recursion: Michal. File clazy.changes of Package clazy----- Mon May 4 18:19:03 UTC 2020 - Christophe Giboudeaux <christophe@krop.fr> - Add upstream patch: * 0001-qstring-allocations-Fix-unit-tests-with-llvm-10.patch ----- Mon Mar 30 21:10:22 UTC 2020 - Christophe Giboudeaux <christophe@krop.fr> - Add upstream patch: * 0001-Fix-build-issues-using-llvm-10...patch ----- Wed Nov 20 23:15:31 UTC 2019 - Simon Lees. The QStringBuilder class is a template class that provides a facility to build up QStrings from smaller chunks. Warning This function is not part of the public interface. Note This class or function is reentrant. Since 4.6. To build a QString by multiple concatenations, QString::operator+() is typically used. This causes n - 1 reallocations when building a string from n chunks. QStringBuilder.

Video: c++ - Qt String Builder in for Schleif

The Eclipse Foundation - home to a global community, the Eclipse IDE, Jakarta EE and over 350 open source projects, including runtimes, tools and frameworks ./perf.2vTnj Reset Zoom Search.

c++ - qstringbuilder - qstringliteral - Code Example

[32;01m * [39;49;00mPackage: dev-qt/qtgui-5.11.3 [32;01m * [39;49;00mRepository: gentoo [32;01m * [39;49;00mMaintainer: qt@gentoo.org [32;01m * [39;49;00mUpstream. In reply to <a href=https://ciscofriend.wordpress.com/2011/12/06/http-installation-of-rhel6centossl-6/#comment-87>itengineer2011</a>. ok keep it up!!

Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview Welcome to LinuxQuestions.org, a friendly and active Linux Community. You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features See also String concatenation with QStringBuilder by Olivier Goffart. Reply Quote 5. 1 Reply Last reply . D. dit8 last edited by . thanks! thats great. I was not aware of that. Reply Quote 1. 1 Reply Last reply.

Using a QStringBuilder might be more efficient in some cases or in some (future) versions of Qt. If you have a specific case where you've profiled the code, found a bottleneck, and found that using an explicit type makes it faster, then I don't see any problem with using the explicit type. I think auto everywhere is an overstatement. Use auto except in cases where there's a good reason not. Dear Julien, I appreciated your quick reply. I could not quite understand the message. Should I delete all CTK directories under Slicer4? Erol On Tue, May 15, 2012 at. ./perf.GSEJY Reset Zoom Search.

qstringbuilder.h source code [include/qt/QtCore ..

Posted: Wed May 24, 2017 11:58 am Post subject: [SOLVED] gcc upgraded to 5.4 --> kde-apps/kleopatr References: . Bug#796274: Removed package(s) from unstable. From: Debian FTP Masters <ftpmaster@ftp-master.debian.org> Prev by Date: Bug#672996: marked as done (libstdc++6-4.6-dev: Static linking of C++ runtime fails due to relocation problems, recompiling with -fPIC needed.) Next by Date: Bug#676558: marked as done (gcc-4.6: Incorrect assembly code generated for loop over char ** in named. The problem is caused by the trailing slash in Cflags: -I${includedir}/ in the pkgconfig file (which is not present when building with autotools)

Hi guys. I've managed to build Qt5 library (5.4.1) on A20 Lime2 board. I'm using A20-OLinuXino-Lime Debian with kernel 3.4.90+ release 3 system. When I try to run any qml app (bin/qml app in the qt instalation dir) i ge [Task Manager] Avoid crash with QStringBuilder. Commit. Fixes bug #420452. Phabricator Code review D29224; KCM LookAndFeel check if splash screen is provided before applying it. Commit. Fixes bug #414417. Phabricator Code review D28656; KCM LookAndFeel check widgetStyle availability before applying it. Commit. Fixes bug #419552. Fixes bug #418698 (In reply to Benda Xu from comment #19) > I concern is that USE=old-kernel has relative meaning across time, it could > mean linux-3.2 this year, and might mean linux-4.4 2 years later. A better > name is more desirable. I don't think that's a problem, in fact I'd say it's an advantage. I don't think we want to end up with multiple USE flags for different kernel versions when we'll.

Qt and QML performance tips & tricks for Qt 4

Gentoo's Bugzilla - Attachment 296127 Details for Bug 395063 [qting-edge overlay] x11-libs/qt-assistant-4.8. fails to buil

Compile issue with latest version · Issue #117

Cc: michaelld@ macports@ removed Keywords: libressl qt4-mac removed : Owner: changed from macports-tickets@ to michaelld Montel Laurent <montel@kde.org> committed rKLEOPATRAe1ae766c0fde: Remove not necessary include moc (authored by Montel Laurent <montel@kde.org>). Jun 18 2017, 6:45 A shit promptly barfed. This is a crappy issue to hit, I have seen it myself numerous times and keep on having to google it due to murkiness. I wont try to formalize why this has changed (my compiler is fixed, so changes in the sysroot and Qt are both up for imolation), what is very clear is that -I/usr/include or even -I/mnt/pi2/usr/include in your compiler line is gonna make the compiler blow. Download visit271-devel-2.7.1-8.sdl6.x86_64.rpm for CentOS 6 from Springdale Computational repository Digital DJ mixing software. 2.3 (beta) branch. @xerus: Updated with the latest dependencies. Regarding the automated udev reloading, I couldn't find any official package providing udev rules that does this, so I'd rather stick to the Arch way and leave it up to the user

[QTBUG-87065] QtWebEngineProcess: undefined symbol

Only POD should be initialized globally. Everything else would need their ctors run on startup, before everything else. This is bad for performance, see e.g.: http. src/kmoretools/kmoretools_p.h. Show First 20 Lines • Show All 76 Lines • Show 20 Line(s): 65: public:: 77: 77 78: bool isInstalled = true;: 78 bool isInstalled. Good morning, I am in trouble, qtwebengine failed to rebuild (after update net-libs/libsrtp) @alan_g installed Ubuntu 16.04 on my notebook directly via Ubuntu Touch (ISODrive is a great tool). Unfortunately the situation here is worse than in my VM on an Ubuntu 20.04 host. I guess the outdated amdgpu for my Radeon Vega 8 Graphics in Ubuntu 16.04 is to blame. The demo runs like in the VM, the same unit test fails, but many smoke tests fail K Desktop Environment Homepage, KDE.org. Report problems with this website to our bug tracking system. Contact the specific authors with questions and comments about the page contents

To: Debian BTS <submit@bugs.debian.org>; Subject: Bug#852671: libkf5kipi: FTBFS (linking error); From: Santiago Vila <sanvila@debian.org>; Date: Thu, 26 Jan 2017 09. FreeBSD Bugzilla - Bug 214758 [NEW PORT] graphics/openorienteering-mapper: Map drawing program from OpenOrienteering Last modified: 2018-05-09 19:38:10 UT /***** qgstipgui.cpp - description ----- begin : Sat Aug 10 2002 copyright : (C) 2002 by Gary E.Sherman email : sherman at mrcc.com *****/ /***** * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later. File chessx-use_system_quazip.patch of Package chessx Index: chessx-1.5.4/chessx.pro ===== --- chessx-1.5.4.orig/chessx.pro +++ chessx-1.5.4/chessx.pro @@ -39,7 +39,6.

Don&#39;t colorize SVG icons if color is transparent

Definition at line 324 of file qstringbuilder.h. Inheritance diagram for QConcatenable< const char[N]>: Public Types: enum { ExactSize = false } typedef const char type[N] typedef QByteArray ConvertTo Static Public Member Functions: static int size (const char[N]) static void QT_ASCII_CAST_WARN appendTo (const char a[N], QChar *&out) static void appendTo (const char a[N], char *&out) Member. Download qt5-5.12.8-x86_64-1_slonly.txz for Slackware 14.2 from Slackonly repository Download qtbase5-dev_5.9.5+dfsg-0ubuntu1_amd64.deb for 18.04 LTS from Ubuntu Main repository KDE Source Cross Reference. Warning, /unmaintained/kdepim/mboximporter/CMakeLists.txt is written in an unsupported language. File is not indexed. 0001 project. Qt Containers QHash QMap QMultiHash QMultiMap Associative Containers We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads

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