Programming Forums > Application Development > C++

Floppie · Feb 18th, 2005, 4:37 PM

I wasn't real sure which to put this in, so I figured C++, as that seems to be where the problem lies.

I was looking to have my webserver output to a timestamped log file instead of its log window, and instead of looking around for info on how to write to a file in VB (reading from a file I had to learn obviously, as it has to read the file and send it), I simply created a function in C++ to add a log line for me.

Anyway, I'm getting this VB run-time error. "Can't find DLL entry point outfile in filestreamdll.dll". I have tried aliasing the function any way I found possible, utilizing any decoration in the .DLL/.LIB files ("?outfile@@YAHABVString@@0ABH@Z" being the total decoration I was able to find), but with any combination of decoration in there I still recieved the error message.

For reference, I'll include any vital info here. This is my complete DllMain() function, as I didn't feel as though I needed any real initialization/deinitialization for it:

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BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
    switch (ul_reason_for_call)
	{
		case DLL_PROCESS_ATTACH:
		case DLL_THREAD_ATTACH:
		case DLL_THREAD_DETACH:
		case DLL_PROCESS_DETACH:
			break;
    }
    return TRUE;
}

The only function's prototype (I enumerated app and trunc to 0 and 1, respectively):

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__declspec(dllexport) int outfile(const String &strOutString, const String &strFile, 
    const int &filemode = app);

String being a standard class I used to make dynamic char arrays easier. The prototype to its relevant constructor is:

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String::String(const char * s);

My attempt at calling the function from VB:

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Public Declare Function outfile Lib "filestreamdll.dll" _
    (ByRef strOutString As String, ByRef strFile As String, ByRef filemode As Integer) _
    As Integer

My attempt at actually utilizing the function from VB:

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outfile_return = outfile("Start Session @" & GetFormattedTime() & Chr$(10), _
    "httplog.log", 0)

GetFormattedTime() returns a string with the date in it, formatted.
If anything else is needed, just say so.

Floppie · Feb 20th, 2005, 12:08 PM

Found my problem. I forgot to create a .def file in my project. I couldn't for the life of me find any way to edit my intial post to add "[solved]" to the title; maybe I'm just being blind, but if a mod could edit that or show me where the edit button is, that'd be great...thank you~

EDIT: Hmm...edit button on this post but not the first. Odd.

Feb 18th, 2005, 4:37 PM	#1
Floppie Newbie Join Date: Feb 2005 Posts: 18 Rep Power: 0	Calling a C++ DLL in VB I wasn't real sure which to put this in, so I figured C++, as that seems to be where the problem lies. I was looking to have my webserver output to a timestamped log file instead of its log window, and instead of looking around for info on how to write to a file in VB (reading from a file I had to learn obviously, as it has to read the file and send it), I simply created a function in C++ to add a log line for me. Anyway, I'm getting this VB run-time error. "Can't find DLL entry point outfile in filestreamdll.dll". I have tried aliasing the function any way I found possible, utilizing any decoration in the .DLL/.LIB files ("?outfile@@YAHABVString@@0ABH@Z" being the total decoration I was able to find), but with any combination of decoration in there I still recieved the error message. For reference, I'll include any vital info here. This is my complete DllMain() function, as I didn't feel as though I needed any real initialization/deinitialization for it: (Toggle Plain Text) BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) { switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: case DLL_THREAD_ATTACH: case DLL_THREAD_DETACH: case DLL_PROCESS_DETACH: break; } return TRUE; } BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) { switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: case DLL_THREAD_ATTACH: case DLL_THREAD_DETACH: case DLL_PROCESS_DETACH: break; } return TRUE; } The only function's prototype (I enumerated app and trunc to 0 and 1, respectively): (Toggle Plain Text) __declspec(dllexport) int outfile(const String &strOutString, const String &strFile, const int &filemode = app); __declspec(dllexport) int outfile(const String &strOutString, const String &strFile, const int &filemode = app); String being a standard class I used to make dynamic char arrays easier. The prototype to its relevant constructor is: (Toggle Plain Text) String::String(const char * s); String::String(const char * s); My attempt at calling the function from VB: (Toggle Plain Text) Public Declare Function outfile Lib "filestreamdll.dll" _ (ByRef strOutString As String, ByRef strFile As String, ByRef filemode As Integer) _ As Integer Public Declare Function outfile Lib "filestreamdll.dll" _ (ByRef strOutString As String, ByRef strFile As String, ByRef filemode As Integer) _ As Integer My attempt at actually utilizing the function from VB: (Toggle Plain Text) outfile_return = outfile("Start Session @" & GetFormattedTime() & Chr$(10), _ "httplog.log", 0) outfile_return = outfile("Start Session @" & GetFormattedTime() & Chr$(10), _ "httplog.log", 0) GetFormattedTime() returns a string with the date in it, formatted. If anything else is needed, just say so.

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Feb 20th, 2005, 12:08 PM	#2
Floppie Newbie Join Date: Feb 2005 Posts: 18 Rep Power: 0	Found my problem. I forgot to create a .def file in my project. I couldn't for the life of me find any way to edit my intial post to add "[solved]" to the title; maybe I'm just being blind, but if a mod could edit that or show me where the edit button is, that'd be great...thank you~ EDIT: Hmm...edit button on this post but not the first. Odd.

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Programming Forums > Application Development > C++

Calling a C++ DLL in VB