Function Reference

Technical Reference > CtAPI Functions > Function Reference

Function Reference

The CTAPI functions allow access to CitectSCADA I/O variable tags via a DLL interface. This allows third-party developers to create applications in C or other languages to read and write to the I/O Devices.

Function	Argument(s)	Type	Description
ctCancelIO	hCTAPI, pctOverlapped	Boolean	Cancels a pending overlapped I/O operation.
ctCiCode	hCTAPI, sCmd, hWin, nMode, sResult, dwLength, pctOverlapped	DWORD	Executes a Cicode function.
ctClientCreate	()	n/a	Initializes the resources for a new CtAPI client instance
ctClientDestroy	hCTAPI	Boolean	The handle to the CTAPI as returned from ctOpen().
ctClose	hCTAPI	Boolean	Closes a connection to the CitectSCADA API.
ctCloseEx	hCTAPI,bDestroy	Handle	The handle to the CTAPI as returned from ctOpen().
ctEngToRaw	pResult, dValue, pScale, dwMode	Boolean	Converts the engineering scale variable into raw I/O Device scale.
ctFindClose	hnd	Boolean	Closes a search initiated by ctFindFirst().
ctFindFirst	hCTAPI, szTableName, szFilter, pObjHnd, dwFlags	Handle	Searches for the first object in the specified database which satisfies the filter string.
ctFindFirstEx	hCTAPI, szTableName, szFilter, szCluster, pObjHnd, dwFlags	Handle	Searches for the first object in the specified database which satisfies the filter string specified by cluster.
ctFindNext	hnd, pObjHnd	Boolean	Retrieves the next object in a search initiated by ctFindFirst().
ctFindPrev	hnd, pObjHnd	Boolean	Retrieves the previous object in a search initiated by ctFindFirst().
ctFindScroll	hnd, dwMode, dwOffset, pObjHnd	Handle	Scrolls to the necessary object in a search initiated by ctFindFirst().
ctGetOverlappedResult	hCTAPI, lpctOverlapped, pBytes, bWait	Boolean	Returns the results of an overlapped operation.
ctGetProperty	hnd, szName, pData, dwBufferLength, dwResultLength, dwType	Boolean	Retrieves an object property.
ctHasOverlappedIoCompleted	lpctOverlapped	Boolean	Checks for the completion of an outstanding I/O operation.
ctListAdd	hList, sTag	Handle	Adds a tag to the list.
ctListAddEx	hList, sTag, bRaw, nPollPeriodMS, dDeadband	Handle	Adds a tag to the list with a specified poll period.
ctListData	hTag, pBuffer, dwLength, dwMode	Boolean	Gets the value of a tag on the list.
ctListDelete	hTag	Boolean	Frees a tag created with ctListAdd().
ctListEvent	hCTAPI, dwMode	Handle	Returns the elements in the list which have changed state since they were last read using the ctListRead() function.
ctListFree	hList	Boolean	Frees a list created with ctListNew().
ctListItem	hTag, dwitem, pBuffer, dwLength, dwMode	Boolean	Gets the tag element item data.
ctListNew	hCTAPI, dwMode	Handle	Creates a new list.
ctListRead	hList, pctOverlapped	Boolean	Reads every tag on the list.
ctListWrite	hTag, sValue, pctOverlapped	Boolean	Writes to a single tag on the list.
ctOpen	sComputer, sUser, sPassword, nMode	Handle	Opens a connection to the CitectSCADA API.
ctOpenEx	sComputer, sUser, sPassword, nMode, hCTAPI	Handle	Establishes the connection to the CtAPI server using the given client instance.
ctRawToEng	pResult, dValue, pScale, dwMode	Boolean	Converts the raw I/O Device scale variable into engineering scale.
ctTagGetProperty	hCTAPI, szTagName, szProperty, pData, dwBufferLength, dwType	Boolean	Gets the given property of the given tag.
ctTagRead	hCTAPI, sTag, sValue, dwLength	Boolean	Reads the current value from the given I/O Device variable tag.
ctTagReadEx	hCTAPI, sTag, sValue, dwLength, pctTagvalueItems	Boolean	Performs the same as ctTagRead, but with an additional new argument
ctTagWrite	hCTAPI, sTag, sValue	Boolean	Writes the given value to the I/O Device variable tag.
ctTagWriteEx	hCTAPI, sTag, sValue, pctOverlapped	Boolean	Performs the same as ctTagWrite, but with an additional new argument.