some errors comed when i install QT4.8.6 on ubuntu16

1.I download the qt4.8.6 source ,and unzip, no problem; 2. ./congure ,no problem; 3.gmake,about 50 errors is comed,just like : “Dialogs/qprintdialog_unix.cpp: In destructor ‘virtual QPrintPropertiesDialog::~QPrintPropertiesDialog()’: dialogs/qprintdialog_unix.cpp:281:19: error: ‘class Ui::QPrintPropertiesWidget’ has no member named ‘cupsPropertiesPage’ delete widget.cupsPropertiesPage;”is one of them. the last error is:”gmake[1]: * [Makefile:128930:.obj/release-shared/qprintdialog_unix.o] error 1 gmake[1]: leaving dir“/home/peter/brill/src/Qt4.8.6/qt-everywhere-opensource-src-4.8.6/src/gui” gmake: * [Makefile:405:sub-gui-install_subtargets-ordered] error2″. can…

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Enabling the submit button, when a user makes the first letter capital (Python-Tkinter)

Is there an easier or simpler way to enable the submit button, when the user makes the first letter of a word capital? (I don’t want the user to submit lower case words) def enable_sumbit_button(*event): self.uppercase_letters = [‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’,’J’, ‘K’,’L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’,…

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I can’t get react up and running. When i type npm start then it gives me an error

As you can see i get this error. Has it something to do with my package.json? Default looks like this. { “name”: “reactproject”, “version”: “0.1.0”, “private”: true, “dependencies”: { “react”: “^16.12.0”, “react-dom”: “^16.12.0”, “react-scripts”: “3.3.0” } } npm ERR! missing script: start npm ERR! A complete log of this run can be found in: npm…

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How to check if

So far I’ve found just one solution: catch an exception, the optional.value() throws. But C/C++ exceptions are very slow, while the code is in the inner loop. The question is strictly about <experimental/optional> (i.e. the std::experimental::optional one), since Clang doesn’t have <optional>. So please save your time by avoiding the usual “You should not use…

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