Hello! Please help - I link msfl11.dll dynamically and init the library after linking (call MSFL1_Initialize) - this is Ok. I OpenDir and Lock security - and read the data - all these are ok. But then I try to write new data with functions MSFL1_WriteDataRec or MSFL1_InsertDataRec it returns the error -100 (As I understand this is MSFL_ERR_INVALID_FUNCTION_CALL. I have MSFL1_WriteDataRec and MSFL1_InsertDataRec in msfl11.dll (I see these function in DLL Export Viewer utility). Please help - what's wrong? Please see code below int nErr = 0; char ch = 0; char cDirNumber = 0; HSECURITY hSecurity = 0; WORD wRecNum = 0; WORD wRecCount = 0; MSFLSecurityInfo_struct SecInfo; SecInfo.dwTotalSize = sizeof (MSFLSecurityInfo_struct); MSFLPriceRecord_struct PriceRec; memset(&PriceRec, 0, sizeof(MSFLPriceRecord_struct) ); DateTime_struct psRecordDate; typedef int (__stdcall *MFOPEN)(LPCSTR, char FAR *, int); MFOPEN pfOpenDir; VERIFY( pfOpenDir = (MFOPEN)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_OpenDirectory") ); nErr = pfOpenDir( ".\\M_Stock_Buf_I", &cDirNumber, MSFL_DIR_FORCE_USER_IN ); typedef int (__stdcall *MFFIRSTSECURITYINFO)(char, MSFLSecurityInfo_struct FAR *); MFFIRSTSECURITYINFO pfFirstSecInfo; VERIFY( pfFirstSecInfo = (MFFIRSTSECURITYINFO)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_GetFirstSecurityInfo") ); nErr = pfFirstSecInfo( cDirNumber, &SecInfo ); // SecInfo correctly filled //MSFLFUNC int __stdcall MSFL1_LockSecurity(HSECURITY hSecurity, UINT uiLockType); typedef int (__stdcall *MFLOCKSEC)(HSECURITY, UINT); MFLOCKSEC pfLockSec = NULL; VERIFY( pfLockSec = (MFLOCKSEC)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_LockSecurity") ); nErr = pfLockSec( SecInfo.hSecurity, MSFL_LOCK_WRITE_LOCK ); // Lock is OK nErr = 0 some temporary ~files in the MetaStock files direcotory. Files intraday WORD dwMaxRec = 0; //MSFLFUNC int __stdcall MSFL1_GetDataRecordCount(HSECURITY hSecurity, // WORD FAR *pwNumOfDataRecs); typedef int (__stdcall *MFGETDATARECORDCOUNT)(HSECURITY, WORD FAR *); MFGETDATARECORDCOUNT pfDataRecordCount; VERIFY( pfDataRecordCount = (MFGETDATARECORDCOUNT)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_GetDataRecordCount") ); nErr = (*pfDataRecordCount)( SecInfo.hSecurity, &dwMaxRec); //dwMaxRec filled with correct number of data records PriceRec.lDate = 20110905; PriceRec.lTime = 1030000; PriceRec.fOpen = 89.0f; PriceRec.fHigh = 92.0f; PriceRec.fLow = 88.3f; PriceRec.fClose = 90.9f; PriceRec.fVolume = 900000.0f; PriceRec.fOpenInt = 0.0f; PriceRec.wDataAvailable = MSFL_DATA_DATE + MSFL_DATA_TIME + MSFL_DATA_OPEN + MSFL_DATA_HIGH + MSFL_DATA_LOW + MSFL_DATA_CLOSE + MSFL_DATA_VOLUME; // WriteDataRec typedef int (__stdcall *MFWRITEDATAREC) (HSECURITY, const MSFLPriceRecord_struct*); MFWRITEDATAREC pfWriteDataRec; VERIFY( pfWriteDataRec = (MFWRITEDATAREC)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_WriteDataRec") ); nErr = (*pfWriteDataRec)( SecInfo.hSecurity, &PriceRec ); // nErr = -100 :( the same result for InsertDataRec with the same parameters nErr = (*pfDataRecordCount)( SecInfo.hSecurity, &dwMaxRec); // dwMaxRec as before - the same :( nErr = 0 // MSFLFUNC int __stdcall MSFL1_UnlockSecurity(HSECURITY hSecurity); typedef int (__stdcall *MFUNLOCKSEC)(HSECURITY); MFUNLOCKSEC pfUnlockLockSec; VERIFY( pfUnlockLockSec = (MFUNLOCKSEC)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_UnlockSecurity") ); nErr = pfUnlockLockSec( SecInfo.hSecurity ); // nErr - 0 after calling - the temporary files disappeared // MSFLFUNC int __stdcall MSFL1_CloseDirectory(char cDirNumber); typedef int (__stdcall *MFCLOSEDIR)(char); MFCLOSEDIR pfCloseDir; VERIFY( pfCloseDir = (MFCLOSEDIR)::GetProcAddress( static_cast<HMODULE>(theApp.GetMSFL11Hinstance()), "MSFL1_CloseDirectory") ); nErr = pfCloseDir( cDirNumber);