CMCDragonkai

Building a Nix Package (The C&C++ Version)

Nix can be used to build any kind of package. But here I'm just going to focus on the simple C&C++ case.

Firstly we have to know that the final built packages will located inside /nix/store. Which is globally readable directory of all build inputs and build outputs of the Nix system. The emphasis is on readable, not writable, that is /nix/store is meant to be modified by the user or programs except for the Nix system utilities. This centralises the management of packages, and keeps our packages and package configuration consistent.

So what exactly are we trying to build. Our goal is to build a directory that will be located in /nix/store/*-package-version/, where * is the hash of the package. Preferably a version is also available, but some C&C++ packages don't have versions, so in that case, there's only /nix/store/*-package/.

What will be inside this directory? It follows the GNU Coding Standards descri

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

pgorczak

import logging

import rospy

# Messages sent to my_logger will not be directed to stdout.
# They will show up in rqt_console with my_logger associated to the node.
logging.getLogger('my_logger').addHandler(rospy.impl.rosout.RosOutHandler())
logging.getLogger('my_logger').setLevel(logging.INFO)

psobot

"""
    multiprocesscallback.py, by Peter Sobot (psobot.com), May 13, 2012
    
    Handles callback functions in classes that have member functions that
    are executed in a different process. A crazy experiment in Python
    magic that breaks a lot of rules.
    
    Do not use in production, for any reason. (Although I do.)
    
    If your class takes in a callback, like so: