大约有 16,000 项符合查询结果（耗时：0.0228秒） [XML]
How can I catch a ctrl-c event?
....h>
#include <stdio.h>
#include <unistd.h>
void my_handler(int s){
printf("Caught signal %d\n",s);
exit(1);
}
int main(int argc,char** argv)
{
struct sigaction sigIntHandler;
sigIntHandler.sa_handler = my_handler;
sigemptyset(&sigIntHandler.sa_...
How to perform Callbacks in Objective-C
.... Here's an example of a custom delegate implementation;
Header File:
@interface MyClass : NSObject {
id delegate;
}
- (void)setDelegate:(id)delegate;
- (void)doSomething;
@end
@interface NSObject(MyDelegateMethods)
- (void)myClassWillDoSomething:(MyClass *)myClass;
- (void)myClassDidDoSome...
Implement C# Generic Timeout
...this with the use of a wrapped delegate that passes out the thread to kill into a local variable in the method that created the lambda.
I submit this example, for your enjoyment. The method you are really interested in is CallWithTimeout. This will cancel the long running thread by aborting it, a...
Why is null an object and what's the difference between null and undefined?
... null
true
A common way of checking whether a variable has a value is to convert it to boolean and see whether it is true. That conversion is performed by the if statement and the boolean operator ! (“not”).
function foo(param) {
if (param) {
// ...
}
}
function foo(param) {
...
String.replaceAll single backslashes with double backslashes
I'm trying to convert the String \something\ into the String \\something\\ using replaceAll , but I keep getting all kinds of errors. I thought this was the solution:
...
Can two Java methods have same name with different return types? [duplicate]
...rameters. If there are no parameters, then you must have different names.
int doSomething(String s);
String doSomething(int); // this is fine
int doSomething(String s);
String doSomething(String s); // this is not
share
...
Add a column with a default value to an existing table in SQL Server
...
ALTER TABLE {TABLENAME}
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL}
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES
Example:
ALTER TABLE SomeTable
ADD SomeCol Bit NULL --Or NOT NULL.
CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated...
Hashing a dictionary?
...thon 3.3 returns different results between sessions). make_hashable() will convert the object into nested tuples and make_hash_sha256() will also convert the repr() to a base64 encoded SHA256 hash.
import hashlib
import base64
def make_hash_sha256(o):
hasher = hashlib.sha256()
hasher.updat...
Virtual/pure virtual explained
...d Virtual() {
cout << "Derived Virtual called.\n";
}
};
int main() {
Base* bBase = new Base();
Base* bDerived = new Derived();
bBase->NonVirtual();
bBase->Virtual();
bDerived->NonVirtual();
bDerived->Virtual();
}
What is the output of this pr...
When is SQLiteOpenHelper onCreate() / onUpgrade() run?
....
SQLiteOpenHelper versions the database files. The version number is the int argument passed to the constructor. In the database file, the version number is stored in PRAGMA user_version.
onCreate() is only run when the database file did not exist and was just created. If onCreate() returns succe...