Object attributes

automatic buffer

Indicates whether buffer memory is managed automatically by the system (TRUE) or is supplied by the user (FALSE). It is initially set to TRUE.

This attribute is not set directly. It is set indirectly using either the useEmptyBuffer or the useFullBuffer method.

If user storage is supplied, this attribute is FALSE, buffer memory cannot grow, and buffer overflow errors can occur. The address and length of the buffer remain constant.

If user storage is not supplied, this attribute is TRUE, and buffer memory can grow incrementally to accommodate an arbitrary amount of message data. However, when the buffer grows, the address of the buffer might change, so be careful when using the buffer pointer and data pointer.

buffer length

The number of bytes of memory in the buffer. The initial value is zero.

buffer pointer

The address of the buffer memory. The initial value is null.

data length

The number of bytes succeeding the data pointer. This must be equal to or less than the message length. The initial value is zero.

data offset

The number of bytes preceding the data pointer. This must be equal to or less than the message length. The initial value is zero.

data pointer

The address of the part of the buffer that is to be written to or read from next. The initial value is null.

message length

The number of bytes of significant data in the buffer. The initial value is zero.