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Is there a performance difference between i++ and ++i in C?
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Executive summary: No.
i++ could potentially be slower than ++i, since the old value of i
might need to be saved for later use, but in practice all modern
compilers will optimize this away.
We can demonstrate this by looking at the code for this function,
both wit...
What's the point of having pointers in Go?
I know that pointers in Go allow mutation of a function's arguments, but wouldn't it have been simpler if they adopted just references (with appropriate const or mutable qualifiers). Now we have pointers and for some built-in types like maps and channels implicit pass by reference.
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mongoDB/mongoose: unique if not null
...ngoDB v1.8+ you can get the desired behavior of ensuring unique values but allowing multiple docs without the field by setting the sparse option to true when defining the index. As in:
email : {type: String, trim: true, index: true, unique: true, sparse: true}
Or in the shell:
db.users.ensureIn...
Add Bootstrap Glyphicon to Input Box
...in Plunker
Note: This presumes you're using glyphicons, but works equally well with font-awesome.
For FA, just replace .glyphicon with .fa
With Bootstrap:
As buffer points out, this can be accomplished natively within Bootstrap by using Validation States with Optional Icons. This is do...
What is a Manifest in Scala and when do you need it?
Since Scala 2.7.2 there is something called Manifest which is a workaround for Java's type erasure. But how does Manifest work exactly and why / when do you need to use it?
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What is the difference between Pan and Swipe in iOS?
...esture is continuous. It begins (began) when the minimum number of fingers allowed (minimumNumberOfTouches) has moved enough to be considered a pan. It changes (changed) when a finger moves while at least the minimum number of fingers are pressed down. It ends (ended) when all fingers are lifted.
C...
What is the purpose of the “Prefer 32-bit” setting in Visual Studio and how does it actually work?
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Microsoft has a blog entry What AnyCPU Really Means As Of .NET 4.5 and Visual Studio 11:
In .NET 4.5 and Visual Studio 11 the cheese has been moved. The
default for most .NET projects is again AnyCPU, but there is more than
one meaning to AnyCPU now. There i...
Performant Entity Serialization: BSON vs MessagePack (vs JSON)
...k is designed to be transparently converted from/to JSON.
MessagePack is smaller than BSON
MessagePack's format is less verbose than BSON. As the result, MessagePack can serialize objects smaller than BSON.
For example, a simple map {"a":1, "b":2} is serialized in 7 bytes with MessagePack, while B...
In SQL Server, when should you use GO and when should you use semi-colon ;?
...S to send the SQL statements between each GO in individual batches sequentially.
The ; is a SQL statement delimiter, but for the most part the engine can interpret where your statements are broken up.
The main exception, and place where the ; is used most often is before a Common Table Expression ...
The difference between the 'Local System' account and the 'Network Service' account?
...the computer will have a service account that has permissions to do practically anything (more specifically the superset of all of the different additional privileges granted to that account).
It is always preferable from a security perspective to run as your own service account that has precisely ...