教我怎么在DELPHI里使用DLL呀

[yagas]

教我怎么在DELPHI里使用DLL呀

[Spacesoft]

晕…… 自己看书去，这样的问题怎么回答嘛……

[biu]

loadlibrary

[softcai]

自己看书去

[yagas]

我没有书呀
小地方
什么都没有

[huojiehai]

动态加载
uses Windows, ...; {On Linux, replace Windows with SysUtils }
type

TTimeRec = record
Second: Integer;
Minute: Integer;
Hour: Integer;
end;

TGetTime = procedure(var Time: TTimeRec);

THandle = Integer;

var

Time: TTimeRec;
Handle: THandle;
GetTime: TGetTime;
...
begin
Handle := LoadLibrary('libraryname');
if Handle <> 0 then
begin
@GetTime := GetProcAddress(Handle, 'GetTime');
if @GetTime <> nil then
begin
GetTime(Time);
with Time do
WriteLn('The time is ', Hour, ':', Minute, ':', Second);
end;
FreeLibrary(Handle);
end;

end;

[huojiehai]

The main source for a dynamically loadable library is identical to that of a program, except that it begins with the reserved word library (instead of program).
Only routines that a library explicitly exports are available for importing by other libraries or programs. The following example shows a library with two exported functions, Min and Max.

library MinMax;
function Min(X, Y: Integer): Integer; stdcall;

begin
if X < Y then Min := X else Min := Y;
end;

function Max(X, Y: Integer): Integer; stdcall;

begin
if X > Y then Max := X else Max := Y;
end;

exports

Min,
Max;

begin

end.

If you want your library to be available to applications written in other languages, it抯 safest to specify stdcall in the declarations of exported functions. Other languages may not support Object Pascal抯 default register calling convention.
Libraries can be built from multiple units. In this case, the library source file is frequently reduced to a uses clause, an exports clause, and the initialization code. For example,

library Editors;
uses EdInit, EdInOut, EdFormat, EdPrint;
exports

InitEditors,
DoneEditors name Done,
InsertText name Insert,
DeleteSelection name Delete,
FormatSelection,
PrintSelection name Print,
...
SetErrorHandler;

begin

InitLibrary;
end.

You can put exports clauses in the interface or implementation section of a unit. Any library that includes such a unit in its uses clause automatically exports the routines listed the unit抯 exports clauses梬ithout the need for an exports clause of its own.
The directive local, which marks routines as unavailable for export, is platform-specific and has no effect in Windows programming.
On Linux, the local directive provides a slight performance optimization for routines that are compiled into a library but are not exported. This directive can be specified for standalone procedures and functions, but not for methods. A routine declared with local
梖or example,

function Contraband(I: Integer): Integer; local;

梔oes not refresh the EBX register and hence

cannot be exported from a library.
cannot be declared in the interface section of a unit.
cannot have its address taken or be assigned to a procedural-type variable.
if it is a pure assembler routine, cannot be called from another unit unless the caller sets up EBX.

[zhksoft]

先看书，别人一时半会不好做答的

[ly_liuyang]

看书
简单的
proc .. stdcall; extrenal dll这样的
看Delphi的Source下很多PAS例如Windows.pas就有了

复杂的动态LoadLibrary和GetProcAddress实现

[mib3000]

mark