Functions

All functions take the buffer by address in pBuffer and return a UINT status: 0 on success, otherwise a DATBUF_ERR_enum value.

datbufInitBuffer

Initializes a buffer. All members of the buffer are reset, maxLength bytes of memory are allocated for the data with TMP_alloc, and the new memory is zeroed.

Direction	Name	Type	Description
In	pBuffer	UDINT	Address of the `datbufBuffer_typ` to initialize
In	maxLength	UDINT	Size of the data storage to allocate, in bytes. Must be greater than `0`.
Return	status	UINT	`0` on success, otherwise a `DATBUF_ERR_enum` value

Error	Cause
DATBUF_ERR_INVALIDINPUT	`pBuffer` is `0`, or `maxLength` is `0`
DATBUF_ERR_MEMALLOC	The memory could not be allocated

Call this function once per buffer, in the _INIT routine. TMP_alloc may only be called in _INIT or _EXIT, so this function must not be called cyclically. The library does not free the allocated memory, so calling it again on a buffer that is already initialized allocates a new block and the old one stays allocated until the controller restarts. B&R notes that allocations larger than about 70,000 bytes can cause cycle time violations in task class 1.

status = datbufInitBuffer((UDINT)&myBuf, 1000);

datbufAppendToBuffer

Copies dataLength bytes from pData to the end of the buffer’s current data and adds dataLength to currentLength.

Direction	Name	Type	Description
In	pBuffer	UDINT	Address of the initialized `datbufBuffer_typ` to append to
In	pData	UDINT	Address of the data to append. The data can be of any type.
In	dataLength	UDINT	Number of bytes to append from `pData`
Return	status	UINT	`0` on success, otherwise a `DATBUF_ERR_enum` value

Error	Cause
DATBUF_ERR_INVALIDINPUT	`pBuffer` is `0`, or `pData` is `0`
DATBUF_ERR_NOTINITIALIZED	`pData` is `0`: the buffer has not been initialized with `datbufInitBuffer`
DATBUF_ERR_BUFFERFULL	The data did not fit in the remaining space. The part that fit was appended.

If currentLength + dataLength exceeds maxLength, only the first maxLength - currentLength bytes are copied, currentLength becomes maxLength, and the function returns DATBUF_ERR_BUFFERFULL. No null terminator is written; see Working with Strings.

status = datbufAppendToBuffer((UDINT)&myBuf, (UDINT)myString, strlen(myString));

datbufClearBuffer

Empties the buffer: currentLength is set to 0 and all maxLength bytes of the data storage are set to 0. The allocated memory is kept for reuse.

Direction	Name	Type	Description
In	pBuffer	UDINT	Address of the initialized `datbufBuffer_typ` to clear
Return	status	UINT	`0` on success, otherwise a `DATBUF_ERR_enum` value

Error	Cause
DATBUF_ERR_INVALIDINPUT	`pBuffer` is `0`
DATBUF_ERR_NOTINITIALIZED	`pData` is `0`: the buffer has not been initialized with `datbufInitBuffer`

Clearing zeroes the entire storage, not only the part in use, so its execution time grows with maxLength.

status = datbufClearBuffer((UDINT)&myBuf);