in reply to Correct call for dll with Win32::API

Is the calling convention used by the DLL the same as the one defined by the WINAPI define (__stdcall)?

I use this script

I don't believe you. 'int HCE300_Read(int TrackNo(int TrackNo,char *ReadData )'?

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Re^2: Correct call for dll with Win32::API
by walto (Pilgrim) on Dec 04, 2008 at 20:15 UTC
    This is the line from the sample C-code:
    int HCE300_Read(int TrackNo, char *ReadData);

    I have no readable documentation of the dll. The data is read from an usb device. Re-reading the documentation of Win32::API I changed the line to: 
    my $readdevice = Win32::API->new (
                    'HCE300_API.DLL', 'HCE300_Read','NP','N') or die $
+^E;
if(not defined $readdevice) {
        die "Can't import API HCE_Read: $!\n";
    }

    [download]
    I am not sure what it does, but it did not help. Perl still crashes.
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      If int HCE300_Read(int TrackNo, char *ReadData); is the prototype, then it uses the default calling convention. It my understanding that's __cdecl for MS compilers. Win32::API uses the __stdcall calling convention since that's what the Win32 API (kernel32.dll, etc) uses.

      Argument-passing orderStack-maintenance responsibility
      __stdcallRight to leftCalled function pops its own arguments from the stack
      __cdeclRight to leftCalling function pops the arguments from the stack

      Win32::API expects the DLL function to reset the stack, but the DLL function expects its caller to reset the stack.

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        Thanks for your help and patience with my lack of C, but does this mean I can not use Win32::API?
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