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What does the thread_local mean in C++11?
...associated with the current thread is used. e.g.
thread_local int i=0;
void f(int newval){
i=newval;
}
void g(){
std::cout<<i;
}
void threadfunc(int id){
f(id);
++i;
g();
}
int main(){
i=9;
std::thread t1(threadfunc,1);
std::thread t2(threadfunc,2);
std...
Should each and every table have a primary key?
...y, rethink your design: most probably, you are missing something. Why keep identical records?
In MySQL, the InnoDB storage engine always creates a primary key if you didn't specify it explicitly, thus making an extra column you don't have access to.
Note that a primary key can be composite.
If y...
What is the HTML tabindex attribute?
...…, "The tabindex attribute, if specified, must have a value that is a valid integer".
– Mark Amery
Mar 26 '17 at 20:46
...
Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
Consider this code:
4 Answers
4
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What is the difference between class and instance methods?
...
Like most of the other answers have said, instance methods use an instance of a class, whereas a class method can be used with just the class name. In Objective-C they are defined thusly:
@interface MyClass : NSObject
+ (void)aClassMethod;
- (void)anInstanceMe...
JAX-RS — How to return JSON and HTTP status code together?
...
Here's an example:
@GET
@Path("retrieve/{uuid}")
public Response retrieveSomething(@PathParam("uuid") String uuid) {
if(uuid == null || uuid.trim().length() == 0) {
return Response.serverError().entity("UUID cannot be blank").build();
}
Entity enti...
converting drawable resource image into bitmap
...rgeIcon);
This is a great method of converting resource images into Android Bitmaps.
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How to get orientation-dependent height and width of the screen?
I'm trying to programmatically determine the current height and width of my application. I use this:
11 Answers
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What is the optimal length for an email address in a database?
...ail address must not exceed 254 characters. As described in RFC3696 Errata ID 1690.
I got the original part of this information from here
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How can I push a specific commit to a remote, and not previous commits?
... push <remotename> <commit SHA>:<remotebranchname>
provided <remotebranchname> already exists on the remote. (If it doesn't, you can use git push <remotename> <commit SHA>:refs/heads/<remotebranchname> to autocreate it.)
If you want to push a commit with...