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How to Call DLL's function?

Hello, I want to call DLL's function at Delphi 4, I have declared the function like this:
procedure openport(n:string);external 'c:\eztt95.dll'

the program can be complied, but while executed the follow statement -- openport('0'), it show a error message--'privilege structure', whatis it mean?

I have use same DLL at VB6, it is workable. the declare statemnet is
Private Declare Sub openport lib "c:\eztt95.dll"(ByVal command$)

the execute statement is
call openport("0")

have I made some mistake with extrenal function declaration?

yk030299

listen

ASKER CERTIFIED SOLUTION

rwilson032697

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yk030299

strange. Why do I become KELVINYU?

yk030299

When I open this page, it show me that
this is my question and I am Kelvinyu
and I have 465pts only.
too strange!

kelvinyu

ASKER

is it?
this question is post by me(kelvinYu)

your link may have some problem

sunsetyang

delphi can only execute dll's function dynamically by load it and execute by load the right function or procedure.
you'd better write like this:
handle=LoadLibrary('xxx.dll');
pProc=GetProcAddress(handle,'FunctionName');
ProcType(pProc)(....);
FreeLibrary(handle);
Above handle is a THandle Type variable,
pProc is a TFarProc Type variable,
ProcType is a type of your calling procedure.

rwilson032697

sunsetyang: This is not true. kelvinyu is using early binding rather than late binding so he does not need to use LoadLibrary or GetProcAddress.

Cheers,

Raymond.

sunsetyang

sunsetyang changed the proposed answer to a comment

sunsetyang

Yeah,I am wrong for the question.
Rwilson,Thank you!

rwilson032697

sunsetyang: Does the change to the declaration work for you?

Cheers,

Raymond.

kelvinyu

ASKER

Rwilson,

I can call the Dll now,
thank you and thanks all

kelvin