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What is the copy-and-swap idiom?

...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided? The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee. How does it wor...
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Print current call stack from a method in Python code

In Python, how can I print the current call stack from within a method (for debugging purposes). 7 Answers ...
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Can I install Python windows packages into virtualenvs?

Virtualenv is great: it lets me keep a number of distinct Python installations so that different projects' dependencies aren't all thrown together into a common pile. ...
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How to set child process' environment variable in Makefile

... I have GNU make 3.81, and all: <\n\t>export PROJ_ROOT=$(CURDIR)<\n\t>echo $(PROJ_ROOT)<\n> outputs the correct expansion for the first row, but only echo for the second one. PROJ_ROOT is not set after running make. Spaces around = gi...
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Duplicate symbols for architecture x86_64 under Xcode

...at defines an Objective-C class or category. While this option will typically result in a larger executable (due to additional object code loaded into the application), it will allow the successful creation of effective Objective-C static libraries that contain categories on existing classes...
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How to set environment variables in Python?

I need to set some environment variables in the Python script and I want all the other scripts that are called from Python to see the environment variables' set. ...
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How to run code when a class is subclassed? [duplicate]

...- Watcher subclasses type, not object. 2 - SuperClass has no superclass at all, not object. I'm just so used to writing down object as a superclass for every class I defined that I somehow missed it that this code was using something else. Although there doesn't seem to be any harm in making SuperCl...
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Restoring Nuget References?

... Try re-installing the packages. In the NuGet Package Manager Console enter the following command: Update-Package -Reinstall -ProjectName Your.Project.Name If you want to re-install packages and restore references for the whole soluti...
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Objective-C categories in static library

...roject as direct dependency (target -> general -> direct dependencies) and all works OK, but categories. A category defined in static library is not working in app. ...
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What is the size of an enum in C?

...set of enum values, but I need each enum value to be 64 bits wide. If I recall correctly, an enum is generally the same size as an int; but I thought I read somewhere that (at least in GCC) the compiler can make the enum any width they need to be to hold their values. So, is it possible to have an e...