Tutorial by Examples: debugging

When json_encode or json_decode fails to parse the string provided, it will return false. PHP itself will not raise any errors or warnings when this happens, the onus is on the user to use the json_last_error() and json_last_error_msg() functions to check if an error occurred and act accordingly in ...
Overview In order to debug Java classes that are called during MATLAB execution, it is necessary to perform two steps: Run MATLAB in JVM debugging mode. Attach a Java debugger to the MATLAB process. When MATLAB is started in JVM debugging mode, the following message appears in the command wi...
The following is an excerpt from Gradle - What is a non-zero exit value and how do I fix it?, see it for the full discussion. Let's say you are developing an application and you get some Gradle error that appears that generally will look like so. :module:someTask FAILED FAILURE: Build failed with...
(All of these are unstable, and thus can only be used from a nightly compiler.) log_syntax!() #![feature(log_syntax)] macro_rules! logged_sum { ($base:expr) => { { log_syntax!(base = $base); $base } }; ($a:expr, $($rest:expr),+) => { { log_syntax!(a = $...
The Python Standard Library includes an interactive debugging library called pdb. pdb has extensive capabilities, the most commonly used being the ability to 'step-through' a program. To immediately enter into step-through debugging use: python -m pdb <my_file.py> This will start the debu...
The JsonPipe can be used for debugging the state of any given internal. Code @Component({ selector: 'json-example', template: `<div> <p>Without JSON pipe:</p> <pre>{{object}}</pre> <p>With JSON pipe:</p> <pre>{{object | json...
A browser's debugging console can be used in order to print simple messages. This debugging or web console can be directly opened in the browser (F12 key in most browsers – see Remarks below for further information) and the log method of the console Javascript object can be invoked by typing the fol...
You can use the node-inspector. Run this command to install it via npm: npm install -g node-inspector Then you can debug your application using node-debug app.js The Github repository can be found here: https://github.com/node-inspector/node-inspector Debugging natively You can also debu...
Debugging with IEx.pry/0 is quite simple. require IEx in your module Find the line of code you want to inspect Add IEx.pry after the line Now start your project (e.g. iex -S mix). When the line with IEx.pry/0 is reached the program will stop and you have the chance to inspect. It is like a ...
Writes an error message to the console if the assertion is false. Otherwise, if the assertion is true, this does nothing. console.assert('one' === 1); Multiple arguments can be provided after the assertion–these can be strings or other objects–that will only be printed if the assertion is fals...
Docker is just a fancy way to run a process, not a virtual machine. Therefore, debugging a process "in a container" is also possible "on the host" by simply examining the running container process as a user with the appropriate permissions to inspect those processes on the host (...
For server side debugging, you'll need to use a tool like Node Inspector. Before you get started, check out some of these useful tutorials. HowToNode - Debugging with Node Inspector Strongloop - Debugging Applications Easily Debugging Meteor.js Walkthrough with Screenshots of Using Node Inspecto...
Besides Node Inspector, some people have reported success with a npm utility called debug. MeteorHacks - Debugging Meteor with npm debug
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The following are the steps to start an Eclipse remote debugger. This is useful when the application is not started from a server instance within Eclipse. This feature is really powerful and can also help debugging code which resides in the test or production environment. Let's have a look at the se...
Use "-x" to enable debug output of executed lines. It can be run on an entire session or script, or enabled programmatically within a script. Run a script with debug output enabled: $ bash -x myscript.sh Or $ bash --debug myscript.sh Turn on debugging within a bash script. It may ...
To be able to debug an application is very important to understand the flow of an application's logic and data. It helps solving logical bugs and adds value to the programming experience and code quality. Two popular gems for debugging are debugger (for ruby 1.9.2 and 1.9.3) and byebug (for ruby &g...
It is possible to use IO.inspect/1 as a tool to debug an elixir program. defmodule MyModule do def myfunction(argument_1, argument_2) do IO.inspect(argument_1) IO.inspect(argument_2) end end It will print out argument_1 and argument_2 to the console. Since IO.inspect/1 returns i...
Debugging is a very powerful way to have a closer look and fix incorrectly working (or non working) code. Run code step by step First thing you need to do during debugging is to stop the code at specific locations and then run it line by line to see whether that happens what's expected. Breakp...
There are several to evaluate a certain expression when debugging a Java application. 1. Manually inspecting an expression When the program execution is suspended at a certain line (either due to a breakpoint or manually stepping through the debugger), you can manually evaluate an expression by se...

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