A DLL is a dynamic link library
In a nutshell, a dynamic link library (DLL) is a collection of small programs, which can be called upon when needed by the program executable (EXE) which is being implemented. The DLL allows the executable to communicate with a specific device as a printer or may contain source code to particular functions.
An example would be if the program (exe) must obtain the free space on your hard drive. He can call the DLL file that contains the function with parameters and a call to the function. The DLL will then tell the executable much space. This allows the executable to be smaller in size and not have to write the function that has already been done.
This program allows all information on the free space, without having to write all of the source code and it saves space on your hard drive too. When a DLL is used in this mode are also known as shared files.
The advantage of DLL files is that, because they do not get loaded into memory (RAM), with the main program, space is saved in RAM. When and if a DLL file is called, then it is loaded. For example, you edit a Microsoft Word document, the printer DLL file does not need to be loaded into RAM. If you decide to print the document, then the printer is loaded DLL file and a call is made to print.
All in all a DLL is an executable file that can not turn on itself, it can run within an executable file. It would be like having a car without an engine, if an executable as a motor.
DLLl To load a file, the executable must declare the function DLL. A DLL can have several different functions in it. Then, if necessary call is made with the required parameters.
Here's what a Declaration and an appeal may look like an executable file. This example is simplified so that you can better understand:
Declare GetFreeSpacex, Kernel32.dll (Drive_Letter, Buffers_If_Any, Value_Returned)
Allows now starting a program and make the call.
The DLL is not loaded into memory until the next line.
GetFreeSpacex "C" Buffers_If_Any, Drive_Letter
We will now tell the user what is the free space on drive C
Use a MessageBox = "The free space on drive C: is" Value_Returned, "bytes"
The appeal required 3 lines of code. Where as if you did not call the DLL file you may have taken 30 or 40 lines of code.
If an appeal or a statement was made incorrectly a GPF (General Protection Fault) can occur. A call to the same DLL, but in a different version may require more or less settings, or the call may not exist. If a DLL or an executable is not the correct version for your OS (Operating System) will cause a GPF or blocking of your machine. To correct errors GPF you must use a tool like Sentry System. Sentry System can show you what appeals are available in a DLL file and what application is an executable file. It can also tell what version is a DLL, and to follow when one is replaced.
Generally newer version of the DLL files are backward compatiable.DLL files Windows ME are not compatible with Windows 98. Many files on Windows ME 98 work well, but not all. The same goes the same for Windows XP and 2003. If you have a dual-boot computer with XP and 2003, you must use the file C:NTLDR and C:Ntdetect.com from Windows 2003. If you are using Windows XP files from 2003 will not boot, but XP. NTLDR is backward compatible.
12.12.2007. 16:02