---- Microsoft Windows provides special libraries (DLLs) called dynamic connectors, allowing the application to share code and resources. The DLL is an executable module including a trunk function that provides services for other procedures. Windows uses a DLL to provide the code and resources for all Windows applications. In addition, the programming can also create a self-employed DLL, sharing code and resources between self-employed procedures.
---- DLL master must have the following goals:
The shared code and resource based on the system of information is based on the system of information.
---- We are now going to study the problem, if you have to develop DLL to expand, increase the functionality of common software, such as: VB4.0, Toolbook3.0, etc.
---- Commonly used to open the DLL platform with Blandc , MS Visualc , both of which have a fixed difference between the DLL, but the most convenient is MS Visualc . I used MS Visualc to send a demo.dll, which defines a function: f1 = (x, y) = x * y. In this example, the DLL's programming structure is revealed, and the powerful software function is increased by the call to Demo.dll.
---- Example:
---- Define a F1 (x, y) = x * y in Demo.dll;
---- Total total needs three documents: demo.h; demo.c; demo.def
* In the header (Demo.h):
#include
EXTERN INT_EXPORT_FAR_PASCAL F1 (INT, INT);
* In the source program (DEMO.C):
#include
#include "demo.h"
Int Far Pascal Libmain (Hinstance Hinstance,
Word WDataseGment,
Word Wheapsize,
LPSTR LPSZCMDLINE)
{
Return 1;
}
INT _EXPORT_FAR_PASCAL F1 (int X, int y)
{
Int data;
DATA = x * Y;
Return Data;
}
INT FAR PASCAL WEP (Int BsystemExit)
{RETURN 1;
}
* In the module file (DEMO.DEF):
Library Demo
Description 'C XYY DLL for Windows'
EXTYPE WINDOWS
Code Moveable Discardable
Data Moveable SingleHeapsize 0
Exports
F1 @ 1
---- * Use DLL in VB:
---- In the calling of the call, you must speak in the Module module, and the speech form is:
Declare function function
LIB "DLL Name" (Byval parameter as datatype,,)
Declare Function F1 LIB "Demo" (byval x as integer,
BYVAL X AS INTEGER AS INTEGER
---- If you can use the function F1 () in any place.
---- * Use DLLS in Toolbook3.0:
---- In the first first first first connected DLL, and sound the function of the function, the speech form is:
Link DLL "Demo.dll"
Function type function name (parameter type,)
INT F1 (int, int)
END LINKDLL
---- Using the above method, it is easy to develop DLL to expand most of the software of VB4.0, Toolbook3.0, Delphi1.0, so that it is more powerful, such as: implementing control of non-standard hardware, fulfil requirements. In this way, I use the visualization of the new software, and combined with the advantages of the C language, the advantages of the program, and the drops of the software are opened.
