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What happen when you open/close a handle?


What happen when you open/close a handle?

By : Dominik Kamiński
Date : November 21 2020, 07:38 AM
hop of those help? hProcess is just a value associated a process. The handle itsself is managed and associated with the process by the Operating System.
code :
HANDLE hProces = 48;
HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, a valid pid);
HANDLE alias = hProcess;
char* ptr;
{
    char c = 'a'; /* similar to the call to OpenProcess itsself */
    ptr = &c;    /* similar to hProcess initialized with the return value
                  * of OpenProcess */
}    /* c goes out of scope, similar to CloseHandle */


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Templating on Enum Value to Select Handle Open/Close

Templating on Enum Value to Select Handle Open/Close


By : user2645801
Date : March 29 2020, 07:55 AM
should help you out I am writing a C++ wrapper for a C library that works with handles represented by integers. There are a bunch of open functions (Aopen, Bopen, Copen, Dopen, Eopen, ...) and corresponding close functions (Aclose, Bclose, Cclose, Dclose, Eclose, ...). I currently have wrapper classes implementing basic RAII, but I have a bit of code duplication, as each of these wrappers differs only in which open and close routine it calls. To get rid of this duplication I was thinking of templating on an enum I define with values for each of the routines (e.g. Atype, Bytpe, etc), and then selecting the correct open and close function at compile time. It would like something like: , You may do something like the following:
code :
template <typename H, H Open(const char*), void Close(H)>
class Wrapper
{
public:
    Wrapper(const char* file) : h(Open(file)) {}
    ~Wrapper() { Close(h); }

    Wrapper(const Wrapper&) = delete;
    Wrapper& operator = (const Wrapper&) = delete;
private:
    H h;
};
How to close a SYSTEM_HANDLE (or some open file handle in another process)

How to close a SYSTEM_HANDLE (or some open file handle in another process)


By : Chandra Bhushan
Date : March 29 2020, 07:55 AM
Any of those help I should have read my own link a little bit better, as wj32 clearly states:
php handle business open and close time

php handle business open and close time


By : hari
Date : March 29 2020, 07:55 AM
I wish this helpful for you Check your $currentTime is less than $rangeStart.
If true then increase $currentTime by one day.
code :
<?php
$currentTime = date('d-m-Y H:i', strtotime("01:14 am"));      
$rangeStart = date('d-m-Y H:i', strtotime("11:00 am"));         
$rangeEnd = date('d-m-Y H:i', strtotime("tomorrow 02:00 am"));

if($currentTime < $rangeStart){
    $currentTime = date('d-m-Y H:i', strtotime("tomorrow".date('H:i',strtotime($currentTime))));     
}


if ($currentTime >= $rangeStart && $currentTime <= $rangeEnd) {
    echo 'in range';         
} else {

    echo 'not in range';        

}
?>
Best way to handle connection open and close with a For loop

Best way to handle connection open and close with a For loop


By : Sutadi Sukarya
Date : March 29 2020, 07:55 AM
will be helpful for those in need First of all, opening and closing a connection in VB.NET doesn't actually open and close database connections. Instead, they will retrieve and return connections from and to the connection pool. So, while there is still some performance impact, it is pretty minimal.
That being said, you can still re-use a connection, perhaps with code like this:
code :
myConnection.Open()
For i As Integer = 0 To 100
    cmd = New SqlCommand("UPDATE <table> where id=@id", myConnection)
    cmd.Parameters.Add(New SqlParameter("@id", i))
    cmd.ExecuteNonQuery()
Next i
myConnection.Close()
Can i re-open a handle after FileStream close it in c#?

Can i re-open a handle after FileStream close it in c#?


By : ginosilver
Date : March 29 2020, 07:55 AM
it should still fix some issue No. The handle is acquired when the file is opened, and becomes invalid once it is closed. Just keep the file open.
The OS keeps a map of handles - really, just integer IDs - for any resource that is allocated. When you release (or, in this case, close) the resource, that map entry is removed, and any locks that were acquired are freed. Any further calls with that handle will start with a map search for the handle, which has been removed, so...
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