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DLL function parameters

Posted on 2003-11-24
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Last Modified: 2010-04-01
Good-day,

I am attempting to load and run a function from a DLL using LoadLibrary and GetProcAddress.  I am able to find out the name of the functions within the DLL using Dependency Walker; but I am unable to find out the number of parameters and the type of parameters that each functions takes (ie float, UINT…).  How would I find out this info?

Thanks.
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Question by:PastorDwayne
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6 Comments
 
LVL 86

Expert Comment

by:jkr
ID: 9811276
>>but I am unable to find out the number of parameters and the type of parameters
>>that each functions takes (ie float, UINT…).  How would I find out this info?

Without a header file or any kind of documentation, there is hardly any chance to find out what arguments the functions take. Bad luck :-(

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LVL 13

Expert Comment

by:SteH
ID: 9811349
Depends on whether the DLL as C++ mangled names. But if the function name has C++ mangling dependency walker will show you the function parameters automatically unless you see only the mangled name. Try hitting the C++ button. Otherwise accept jkr comment, no other chance.
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LVL 86

Expert Comment

by:jkr
ID: 9811381
>>But if the function name has C++ mangling dependency walker will show you the function parameters

Only for simple data types. Sth. like

struct TheHellOfALotData {

// content goes here

};

int foo ( TheHellOfALotData*);

it'll come up with 'a pointer' at best...
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Author Comment

by:PastorDwayne
ID: 9811703
Alright; Assuming one of the parameters is an array, how could this be passed to GetProcAddress? For an UINT I use

typedef UINT (CALLBACK* LPFNDLLFUNC1)(UINT);

What would the typedef be for an array on integers? Would a pointer have to be passed instead?
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LVL 86

Accepted Solution

by:
jkr earned 125 total points
ID: 9811735
>>What would the typedef be for an array on integers?

typedef UINT (CALLBACK* LPFNDLLFUNC1)(UINT*);

>>Would a pointer have to be passed instead?

Yes, indeed. But, unless you are sure about what parameters the function takes, this is more than risky...
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Author Comment

by:PastorDwayne
ID: 9811817
Thanks for your time.
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